Having sharp pains under the left breast can be a scary experience. Fortunately it usually does not mean anything serious. It can be due to temporary musculoskeletal pain and will pass on its own. In other instances, this type of pain can be the result of a more serious medical condition that needs medical attention. If you have any doubts about the cause of the pain, seek medical attention so that the cause can be uncovered and treated if necessary.

What Does Sharp Pain Under Left Breast Indicate?

There are many reasons why you might have sharp pains under the left breast. They range from mild conditions to those that are severe. Here are some reasons why you might have this type of pain:

Problems with Digestive System

• Excessive digestive gases. Your stomach is located on the left side of your abdomen and can be filled up with gas when you swallow. These trapped gases can trigger nerve pain in the stomach which is experienced as sharp pain under left breast.
• Heart burn. Heart burn is a common cause of chest pain, particularly beneath the left breast. It is caused by stomach acid that travels up the esophagus and irritates the esophageal mucosa.

• Hiatal hernia. A hiatal hernia happens when there is a hole in the diaphragm that allows bowel or stomach contents to travel up inside the chest cavity. When you have this condition, you can experience symptoms of chest pain, bloating sensations after eating, heart burn, and difficulty breathing.
• Gastritis. Gastritis is an inflammation of the stomach lining, which can be caused by infections you get from drinking contaminated water or eating contaminated food. Because the stomach is found on the left side of the body, inflammation of the stomach lining can be experienced as left-sided chest wall pain. Other symptoms include nausea, indigestion, vomiting, and bloating.

Problems with the Chest

• A chest cyst. You can develop a cyst on the chest wall that irritates the nerves of the muscles in the chest wall. You may or may not be able to feel the cyst yourself yet it can cause pain.
• Rib injuries or pain in the intercostal muscles. You can have inflammation and pain from trauma to the chest or just from an inflammatory response affecting the joint that connects the ribs to the sternum. This can lead to sharp pain called costochondritis. It can be very intense but does not represent anything serious.
• Injury to the chest wall. You can have a crushing injury to your chest wall from a motor vehicle accident or a fall. This can set up sharp pain under left breast that may mean you have fractured a rib or sprained the muscles of the chest wall itself.
• Chest wall inflammation. You can have inflammation of the musculoskeletal parts of your chest wall. This can lead to sharp pain.
• Precordial catch syndrome (PCS). This is an intense type of chest pain, usually occurring on the left side. It is worse when you take a deep breath and lasts just a few seconds. Pain from this condition can recur over a period of about 30 minutes. People who have this condition feel as though there is a “bubble” in their chest. When the “bubble” pops, the pain is relieved. This can happen repetitively, ranging from many times a day to every few years apart.

Problems with Cardiovascular System

• Pericarditis. This is a more serious problem that can lead to left-sided chest pain. Pericarditis involves an inflammation of the pericardial sac that surrounds the heart. Other symptoms you may experience as a result of having pericarditis include palpitations of the heart, sharp chest pain on the left side, nausea or weakness, and fever. There can also be swelling of the abdomen or leg, shortness of breath or a harsh cough. Pain from pericarditis usually is worse when taking a deep breath, coughing, or lying down. The pain often travels from the chest to the left shoulder or neck.
• Heart conditions. When you have blocked arteries in your heart, you can experience angina, which is pain felt usually on the left side of the chest, although it can radiate to the left hand, shoulder, back, neck, or jaw.

Other Factors

• Stress. Many people have chest pains when under a great deal of stress. There is nothing really wrong with the body but the stress causes nerve inflammation nevertheless. Chest pain from stress is usually sharp in nature and can be very painful. When you relax, the pain usually goes away. 
• Problems with the lungs. The pleura is the lining of the lungs and its function is to allow smooth motions of the lungs when you breathe. Sometimes the pleura can become inflamed due to chemical exposure, trauma, or infection. This can cause sharp pain beneath left breast.

One Patient's Experience with Sharp Pain Under Left Breast

I have been experiencing a month-long sharp pain occurring on my left side beneath the breast. It has been associated with sweating, nausea, vomiting, shortness of breath, fainting feelings, a racing heart and dizziness. Now the chest pain has sharpened and does not go away. It gets worse whenever I twist my body, change to a new position, or take a deep breath. It feels like a muscle contraction at times. I am 27 years old and have a history of breast cancer and heart diseases in my family. A recent mammogram returned as normal. I have taken medications for the pain and this has not helped. 

The doctor answered as such:

This type of pain is unlikely to be related to your heart. Heart pain does not get worse with movement as you described. The most likely cause of your pain is a condition known as costochondritis. This is an inflammation of the cartilage that connects the ribs to the breast plate. You may also be suffering from chest wall irritation or inflammation of the lining of the lungs. Muscle spasm is also a possibility.Anxiety can be part of this type of pain so you need to be rest assured that it is not dangerous. 

What Can I Do to Relieve Sharp Pain Under Left Breast?

• Take NSAID medication. If your pain is caused by chest wall or pleuritic inflammation, the best thing you can do is to take nonsteroidal anti-inflammatory medication to relieve the inflammation. It may take a few days to take effect but is generally an effective way to treat this type of pain.
• Removal of a chest cyst. If a cyst is causing your pain, you can undergo surgery to remove the cyst. Once the cyst has been removed, you are unlikely not experience the pain again.
• Relax. As chest pain is often associated with anxiety, the more you relax, the more able you are to handle and relieve the pain. Try meditation or other relaxation techniques to calm your mind.
• Hot or cold packs. They can be placed on the set of your pain, relieving the inflammation and muscle spasm that might be the underlying cause of the discomfort.
• Alter your lifestyle or diet. The pain in your chest may be due to gastrointestinal troubles. Changing your diet can relieve inflammation of the gastric lining and ease the pain you are experiencing. Try not to eat too much if you have a hiatal hernia because it can put extra pressure on the diaphragm, pushing the stomach contents into the chest cavity.
• Antibiotics. If the pain in your chest is from a breast infection, the most common treatment is antibiotics to heal it.