Pain In or Under the Left Breast

What to Do If You Have Left Breast Pain

Sudden sharp pain under the left breast in females could have many possible causes, such as injury, infection, hormones, and lung problems. These conditions may cause pain in or under the breast. Depending on the condition, there may be other symptoms as well.

In some cases, sudden sharp pain under the left breast in females can be a sign of a life-threatening condition, such as a heart attack, pulmonary embolism, or cancer. For this reason, you should always have breast pain evaluated by a healthcare provider before considering other causes.

This article will walk you through the causes of left breast pain, the other symptoms to watch for, and when to see your healthcare provider.

breast related causes of left breast pain

Verywell / Emily Roberts

Heart-Related Causes of Pain in the Left Breast

Some causes of left breast pain are related to the breast itself; others are not. Because left breast pain can be a symptom of a heart attack, however, it is important to rule out this cause first.

If you're not sure where your pain is coming from, get immediate medical attention. Call 911 if you think you may have symptoms of a heart attack.

Heart Attack Symptoms

The symptoms of heart attack in females may include:

  • Mild pain
  • Burning
  • An uncomfortable feeling in the breast

These are often different than symptoms of a heart attack in males. Unfortunately, the often vague and subtle symptoms lead women to overlook the signs. Too often, that's a fatal mistake.

Everyone should be familiar with the symptoms of a heart attack. They may include:

  • Chest pain or pressure (not present in up to a third of people having a heart attack)
  • Pain in your neck, jaw, or left arm
  • Shortness of breath (especially common in women)
  • Sweating
  • Nausea
  • Lightheadedness or passing out
  • A feeling that something isn't right or a sense of impending doom

The Origin of Left Breast Pain

Left-sided breast pain can originate in the breast itself or in other nearby structures. It can be hard to pinpoint the source.

The location of pain isn't always the same location as the problem. Some nerves are very specific. For example, if you feel a sensation on your fingertip, it's likely caused by something at that site.

Other nerves aren't as specific. They alert you to the general area of a problem, not the precise location.

It's common not to know whether your pain is in your breast or in something close to it.

Breast-Related Causes

Several breast conditions may cause pain in or under the left breast. They include:

  • Injuries, such as muscle strain
  • Breast surgery
  • Milk duct conditions and infections
  • Hormonal causes
  • Lumps

Injuries

Your breasts are covered with sensitive, elastic skin that protects:

  • Nerves
  • Blood vessels
  • Connective tissues
  • Ducts and lobes for producing breast milk

If you've had a breast injury, bruising and aches may last until the injury heals.

Sometimes an injury to the breast causes scar tissue. Scar tissue can cause pain and fat necrosis, a breakdown of fatty tissue. It may appear as a hard lump. These lumps are hard to distinguish from breast cancer, even on a mammogram.

If you are experiencing mild breast pain due to a minor injury, use the following to reduce pain and inflammation:

  • Wrap an ice pack with a towel and apply it to the injured breast for 10 to 15 minutes to reduce swelling.
  • Take an NSAID medication for pain relief, such as ibuprofen (Advil) or naproxen (Aleve).
  • Avoid wearing bras that are tight or have underwires.

Contact your healthcare provider if your pain does not improve after icing and using painkillers.

Breast Surgery 

After any type of breast surgery—augmentation, reduction, or reconstruction—your breasts will hurt as the incisions heal and scar tissue develops.

As with scar tissue from an injury, pain can come and go long after your surgery. Depending on the type of surgery, you may experience:

  • Burning pains in your nipples
  • Sharp, shooting pains in your breast
  • A tightness or cramping sensation in your breasts, shoulders, neck, and back
  • Nerve pain (burning, pricking, or shock-like sensations) in the breast, chest, arm, or armpit

Your healthcare provider will likely prescribe painkillers for your recovery. They may also provide instructions for hot and/or cold compresses to help relieve breast pain and swelling. Take care to follow their instructions carefully.

If you still experience pain despite taking painkillers, let your healthcare provider know. In some cases, prolonged pain following surgery can be a sign of nerve damage caused by the surgery itself. Your provider can prescribe medication to help with nerve pain.

Milk Duct Conditions and Infections

Several benign but painful conditions can develop inside your breast milk ducts.

  • An abscess under your nipple or areola can cause pain, redness, and heat.
  • Milk ducts can become clogged, causing a firm, tender lump.
  • Mastitis is an infection in a clogged duct. It makes the breast swollen, tender, warm, and red.
  • Ductal ectasia is another possible infection. It causes tenderness, irritation, redness, and possibly a thick, sticky discharge from the nipple.
  • Breast cysts and fibroadenomas are growths that may crowd breast structures, creating aches and pains.

If you suspect a breast infection or inflammation, see your regular healthcare provider or gynecologist. You may need antibiotics or other prescription medications.

Most breast cysts go away by themselves and do not require any treatment, although a lump in the breast should always be checked by a healthcare provider to ensure it is benign (not harmful). Clogged milk ducts also tend to resolve on their own without treatment.

To ease pain caused by a breast cyst or clogged milk duct, you can take an over-the-counter painkiller like ibuprofen or acetaminophen. Applying a warm compress to the sore breast may also be helpful.

Hormonal Causes

Hormone changes may cause breast tenderness. That's especially true during the fluctuations of your menstrual cycle. 

Other causes include taking hormones for:

  • Oral contraception (birth control pills)
  • Infertility treatments
  • Hormone replacement therapy

You may feel pain in one or both breasts. It may be worse on one side. You might also feel it in your armpit.

Some thyroid diseases can lead to benign (noncancerous) breast changes that cause pain. These include:

The nature of the pain along with how it's treated depends on the specific breast changes. If your pain is a side effect of another medication, your provider may switch your treatment to one that has a lesser effect on your hormones.

For breast pain due to thyroid dysfunction, your pain should resolve once your thyroid condition is under control. Treatment will likely entail thyroid medication (e.g. levothyroxine for hypothyroidism) to return your thyroid hormones to a healthy level.

Lumps

Breast lumps can show up at certain stages of your menstrual cycle. If you find lumps at other times, see your healthcare provider right away. It's even a good idea to get lumps that are related to your cycle checked out.

Your provider can take the steps necessary to see whether a lump is benign or malignant (cancerous). They'll likely use imaging tests and possibly a biopsy.

Pregnancy

Under the influence of the hormones estrogen and progesterone, breasts undergo many changes during pregnancy to prepare for lactation (milk production) and the possibility of breastfeeding.

As the breasts develop and increase in size and volume, you may notice that they feel especially tender and full and that the nipples are more sensitive.

Tender, swollen breasts are often one of the earliest signs of pregnancy, appearing as early as one to two weeks after conception.

Many people find that applying a cold compress to sore breasts is helpful. Wearing loose clothes and a well-fitted bra for extra support is also recommended.

Left-Sided Breast Cancer

Breast cancer is usually—but not always—painless in the early stages. A notable exception is inflammatory breast cancer.

This is an aggressive breast cancer that usually begins with:

  • Pain
  • Redness
  • Swelling in the breast

This cancer often resembles an infection. Most of the time, you can't feel a lump. The only early symptom may be pain in one breast.

Breast cancer in female breast tissue occurs slightly more often on the left side than the right. It occurs equally on both sides in male breast tissue.

Breast pain is likely due to something other than cancer. Nonetheless, if you feel a lump in your breast or are experiencing unusual swelling, with or without pain, you should always see a healthcare provider for an evaluation.

Non-Breast Related Causes

Non-breast related causes of left breast pain

Verywell / Emily Roberts

It can sometimes be hard to tell where pain is centered. You may feel it in your left breast while it actually comes from beneath it.

Some non-breast conditions you may feel in your breast include:

Chest Wall Pain

Below your breast are chest wall muscles. They may spasm when you're anxious or stressed. That can cause pain that lasts for a few seconds or several days. You may also experience chest wall pain if you strain a muscle in your chest or you have a bruise or rib fracture.

Chest wall pain from inflammation of the cartilage between the breastbone and ribs is called costochondritis. It is similar to another condition called Tietze syndrome, which can also cause local swelling. Costochondritis and Tietze syndrome usually get better within a few days to weeks. An NSAID should help with the pain.

Chest wall pain can also be caused by precordial catch, a benign condition associated with brief, sharp pain on the left side of the chest.

Chest wall pain can appear on either side, though it's less common on the right. It can range from mild to severe. It's usually painful to the touch. The pain may radiate to your back or stomach and can feel sharp or stabbing.

It may get worse when you take a deep breath. Pains may even shoot down your arms.

You can treat minor chest wall pain by taking an NSAID and applying a cold compress to the affected area. If the pain doesn't improve despite taking a painkiller, let your healthcare provider know.

Digestive Causes

Your esophagus is the tube that connects your mouth and stomach. It runs below your left breast.

Pain from the esophagus may be a burning pain, like heartburn. You may have other symptoms like an acidic taste in your mouth.

Sometimes gastroesophageal reflux disease (GERD) can feel like left breast pain. A related condition called hiatal hernia may cause similar symptoms.

For mild heartburn, your healthcare provider may recommend an antacid and avoidance of acidic, high fat, or spicy foods and drinks. For more severe cases of GERD, you may be put on an acid-reducing medication, such as an H2 blocker or a proton pump inhibitor.

You should notice an improvement in your pain once the digestive problem is under control. If you don't, let your healthcare provider know.

Fibromyalgia

Fibromyalgia is a chronic pain condition. It can cause pain anywhere in your body. Chest pain, including costochondritis, is fairly common.

Fibromyalgia pain comes from a disordered nervous system. It affects not only nerves, but muscles, joints, and connective tissues. The pain it creates can be generalized and diffuse or sharply focused.

The nature of the pain can be dull and achy, sharp, stabbing, burning, or tingling. Fibromyalgia pain is notably not tied to inflammation, redness, or warmth.

Very often, fibromyalgia pain is made worse with gentle pressure. This is called tactile allodynia.

While there is no cure for fibromyalgia, several therapies are available to help with pain. First-line treatments include the following drugs:

  • Amitriptyline (Elavil), an antidepressant that reduces pain and anxiety and improves sleep
  • Cyclobenzaprine (Flexeril), a central nervous system relaxant that treats pain and muscle spasms
  • Gabapentin (Neurontin), an anticonvulsant (anti-seizure) medication that treats nerve pain

Lung-Related Causes

Your lungs sit behind your breasts. A few lung-related conditions can cause pain that's mistaken for breast pain. They include:

  • Pneumonia: This lung infection causes inflammation in the air sacs. Treatment may involve antibacterial, antiviral, or antifungal medication, depending on the type of infection you have.
  • Pleurisy: This is an inflammation of the membrane that covers your lungs. Treatment involves NSAIDs for pain. Or, if those are not inadequate, your healthcare provider may prescribe a stronger painkiller, such as codeine.
  • Pulmonary embolism: This is a blood clot that blocks a blood vessel in the lungs. Depending on its severity, treatment may involve an anticoagulant (anti-blood clotting) medication, the use of a catheter to diffuse the blood clot (catheter-directed thrombolysis), or surgery.

Pulmonary emboli are medical emergencies that require immediate treatment. Other symptoms to be aware of include sudden shortness of breath and coughing.

Skin-Related Causes: Shingles

Sometimes pain feels like it's either in the skin or on the outer surface of the breast. This may be shingles.

That's a condition caused by reactivation of the virus that causes chickenpox (the varicella-zoster virus). It can come on years or decades after you have chickenpox.

The initial tenderness is generally followed by a painful rash. Because the rash is the more recognizable symptom, shingles can be hard to recognize early on.

Treatment for shingles involves taking antiviral medication, such as the drugs acyclovir, brivudin, valaciclovir, or famciclovir. Pain and other shingles symptoms should resolve once the infection is treated.

When to See a Healthcare Provider

Left-sided breast pain has many causes. Some are more serious than others. The only way to know for sure what's causing your pain is to get medical attention. 

Pain is your body's way of alerting you to a problem. Don't ignore it or assume it's harmless.

If your healthcare provider doesn't find an explanation for your pain, keep pushing for one. If pain persists, consider getting a second opinion.

It's not unheard of to have more than one cause of left breast pain. For example, you may have a breast cyst along with costochondritis.

When to Call a Healthcare Provider

Call a healthcare provider for your breast pain if:

  • It lasts longer than two weeks.
  • It stays in one spot.
  • It gets progressively worse.
  • It limits your activity.
  • You have a painful lump that doesn't go away after your period.
  • Your breasts are red or swollen.
  • You have pus drainage or nipple discharge.

Summary

The first thing to do when you have sudden sharp left breast pain is to get checked for a heart attack.

Left breast pain can come from injuries or conditions that affect the breast tissue and milk ducts. Breast cancer isn't usually painful early on. An exception is inflammatory breast cancer, which also causes redness and swelling.

Pain from other areas felt in the left breast can come from nearby structures like chest muscles, the lungs, or the esophagus. Nerve pain in the area can be from fibromyalgia or shingles.

See your healthcare provider about left breast pain so you can have it diagnosed and treated.

Frequently Asked Questions

  • Why do I have pain under my left breast when I breathe?

    A sore muscle will hurt more when you inhale. But if you also have symptoms such as a cough or fever, you could have inflammation of the membrane around your lungs and chest (pleurisy) or a respiratory infection such as pneumonia.

  • Can massage ease breast pain?

    Massage can help with certain types of pain. It can reduce pain related to breastfeeding. If you have a pulled muscle in the chest around your breast, an appropriate massage may also relieve the pain.

  • Can my bra cause breast pain?

    Yes. Make sure you wear the appropriate-size bra with proper support for your chest size. Incorrect fit can cause sagging and pulling, which causes breast discomfort.

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Additional Reading

By Lynne Eldridge, MD
 Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."