Pain under your left breast can have many different causes, from discomfort like heartburn to a serious condition like a heart attack. A doctor can make a diagnosis based on your symptoms. If you have sudden, severe pain, seek emergency medical care.

The left side of the body houses several vital organs. Under and around the left breastbone are the heart, spleen, stomach, pancreas, and large intestine.

The left lung, breast, and kidney are also present, although they sit higher in the body than the right one.

When you experience pain under the left breast, it can have a variety of causes — some simple, some serious.

Pain under your left breast can be related to multiple organs or body systems. It is usually related to organs in the upper left side of the body, such as the stomach, heart, lungs, pancreas, and spleen.

The causes are usually heart-related, digestive, or related to problems in the breast itself.

That said, where you feel the pain isn’t always related to where the pain originates from. Some causes don’t fall into any of these categories.

  • Heart attack:This can cause left-sided pain under the breast because the heart is located left and center in the chest.
  • Pericarditis: This is an inflammation of the pericardium, the thin, two-layered membrane that surrounds the outside of the heart. Pain occurs when the irritated membrane rubs against the heart.
  • Precordial catch syndrome: this condition occurs when the nerves of the chest wall become pinched or irritated. It can cause sudden stabbing pain around the left breast that can mimic a heart attack but resolves on its own.
  • Angina: This develops when the heart muscle doesn’t get enough oxygen from the coronary artery and can result in discomfort below the left breast.
  • Gastritis: This causes inflammation of the stomach lining, which is in the upper region of the left side of the body.
  • Pancreatitis: This is inflammation of the pancreas. It tends to develop on the left side of the abdomen and may be felt higher up near the breast.
  • Heartburn: This occurs when digestive acids erode the lining in your esophagus (windpipe), which creates a burning sensation in your throat. But some people may feel it behind the left breastbone and mistake it for a heart attack.
  • Pleurisy: This condition results when the membrane surrounding the lungs and lining the inside of the chest cavity becomes irritated and inflamed. It causes chest pain when breathing that may be felt around the breast.
  • Costochondritis: This is an inflammation of the cartilage that attaches the ribs to the breastbone. It can affect either side of the chest near the breasts.
  • Spleen injury: The spleen is an organ to the left of the stomach that filters blood primarily. When the spleen is injured or ruptures, it can leak blood into the abdominal cavity, irritating it. Since both the spleen and stomach sit on the left side of the body, upper-left pain near the breast area is possible.
  • Hiatal hernia: This occurs when the stomach pushes through the diaphragm into the chest, causing digestive acid to reflux into the esophagus. This often causes pain in the upper left portion of the body that can radiate to the breast area.
  • Pregnancy: As a baby grows inside the womb, it can begin to push against the lungs and chest, which can cause pressure in the breast area, as well as heartburn.

Any sudden, abnormal, or debilitating pain — left side or otherwise — needs immediate medical attention. While not an exhaustive list, seek emergency care if you have:

  • tightness or pressure in the chest, especially if you’ve been diagnosed with heart problems or the pain is accompanied by sweating, nausea, and shortness of breath
  • trouble breathing
  • an injury to the chest
  • changes in your stools — either you can’t pass them, or they look bloody, oily, or resemble tar
  • pain that doesn’t improve with rest or starts to radiate to other parts of the body

Which organ is under the left breast?

The heart, spleen, stomach, pancreas, and large intestine are located under the left breast.

Why do I have pain under my left rib cage?

Many of the same conditions that can cause left-sided chest pain can also cause rib pain. Other causes include a broken rib, Irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and kidney stones.

How do I know if my breast pain is heart-related?

The symptoms of a heart attack include chest pain, stomach pain, irregular heart rate, sweating, shortness of breath, and dizziness. However, some people may experience different symptoms, especially females assigned at birth (FAABs). These include fatigue, anxiety, and shoulder, throat, or jaw pain. Some people may have mild symptoms like heartburn, which is why heart attacks can be hard to recognize in some cases.

WHEN TO CALL 911

Any time you have pain or pressure in your chest that lasts more than a few minutes and is different from the pain you’ve felt before, it’s important to get medical attention as soon as possible. This is especially important if you have any of the

Learn more: What does a heart attack feel like? and warning signs of a heart attack.

Given the vital organs located there, pain under the left breast isn’t uncommon.

In most cases, it’s not a heart attack. But because the pain can be intense and the symptoms worrisome, it’s worth getting them evaluated. In many cases, the conditions can improve with medication and lifestyle adjustments.