There are a number of possible causes of pain on left side of chest under arm. This region can be medically referred as Axilla and the pain as Axillary pain. Causes of pain on left side of chest under arm are versatile and can range from mild to severe and the pain on left side of chest under arm can be attributed to irritation, infections, compressions, or even cancers in structures associated like sweat glands, nerves, lymph nodes, muscles etc.

Pain on left side of chest under arm can be referred from some other site of infection, injury or even heart related issues.

The area is sensitive and has good supply of nerves and blood vessels so it is very common to experience pain on left chest side of chest under arm or either arm as a matter of fact.

Some common causes, some serious causes will be discussed in the article below, continue reading to get a sigh of relief or an urgent medical care.

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Common causes of pain on left side of chest under arm

Cervical discopathy: Discs between the vertebra in cervical region when start to degenerate results in pain and that radiates to the arm, hand and can cause pain in left side of chest under arm

TOS( thoracic outlet syndrome): by compressing surrounding structures and nerves in particular can cause pain in left side of chest under arm.

Pulmonary causes: Bullous rupture can happen spontaneously and cause in left side of chest under arm.

Pleurisy and some infections: This condition can irritate the linings of lungs called pleura and cause its inflammation, and results in pain which can exacerbate during breathing and also radiate to left side of chest under arm.

GERD / heartburn and PUD (peptic ulcer disease): both can lead to pain in left side of chest under arm.

Musculoskeletal strain and injury: Tear or injury due to overuse in any activities like lifting, and other sports acitivity can cause significant damage in any associated muscle in the left side of chest and under arm like teres major, latissimus dorsi, pectoralis major and even coracobrachialis can cause pain on left side of chest under arm.

Injury of nerves in the area can also result in significant damage such as Brachial plexus due to any forced pull or push can cause pain on left side of chest under arm and even on other side depending on the site of injury.

Heart Disease: Usually chest pain is always expected as a matter of fact when heart diseases like coronary artery disease (CAD) are concerned, but significantly a vague pain in arm pit alone is also experienced in people especially women with heart disease. The pain can be felt on left side of chest under arm along with discomfort in areas like nausea, jaw pain or any general feeling of discomfort.

Angina: This pain is felt on the left side of chest under arm and is due to lack of oxygen supply to heart due to narrowing of artery or a block.

Associated symptoms of fatigue, dizziness, difficult breathing can be seen.

If associated symptoms along with pain on left side of chest under arm are noticed, it is an alarming situation and doctor is needed to avoid any serious issue.

The underlying issues like heart diseases and obesity can be treated with life style modification and medications. Quitting smoking, managing hypertension and physical activities can be counted in lifestyle modifications.

Peripheral Artery Disease: Like the blood vessels which are narrowed inside heart cause chest pain likewise blood vessels supplying the arm particularly on your left side if gets occluded can result in pain under arm.

Pericarditis: The pain caused due to the inflammation of lining/ sac around the heart. Pericarditis has many associated symptoms along with pain on left side of chest under arm. It usually gets worse with changing positions, breathing or swallowing food.

Varicella zoster virus: This virus causes chickenpox and when it reactivates as shingles can particularly result in pain and can be on left side of chest under arm and can involve either side. It causes a painful rash and is seen commonly in chest, arm and underarm settings.

There are associated symptoms of infections which involve tingling, burning, itching etc.

Breast cancer: Breast cancer may at first present with no or little symptoms and once the lymph nodes get involved may result in pain under arm alongside chest pain.

If any abnormalities are noticed around the chest or in the under arm doctor should be consulted to get the condition examined and intervened before it gets worse.

Shaving: Cleaning the armpit area ineffectively can cause pain in the area and in fact using dirty blades or under unhygienic conditions can even result in infections and can cause pain on left side of chest under arm but obviously can be found on the right side as well

Swollen lymph nodes/ enlarged axillary nodes:

There are a number of potential causes of enlargement of lymph nodes which involves infection, autoimmune disease and cancer.

Infections due to HIV, bacteria and other parasites can cause tenderness and enlargement of lymph nodes and even lymph nodes draining from other infectious sites like abdomen, chest can cause significant pain, like pain on left side of chest under arm due to the infection in chest and enlarged lymph nodes.

Cancer:  A number of cancers like breast, lung cancers and melanomas can spread to axillary lymph nodes and cause significant lump on the particular side usually unilateral and may be the first presenting symptom of cancer. Like breast cancer or lung cancer may cause pain on left side of chest under arm.

Lymph nodes in cancer are immobile and non-tender unlike other enlarged lymph due to some causes but there might be some exceptions to it.

Lymphedema: When lymph drainage is interrupted due to any surgery particularly breast related surgery can lead to swelling of that particular side and deep ache in armpit. This can result in overall pain on left side of chest under arm or on either side depending on the side of surgery site.

Bacterial and fungal infections:

Fungal infection like ring worm usually infects the body and can grow in any part of the body particularly moist areas. Armpit is an area in which the fungus can thrive very well and result in pain that can radiate to corresponding part of chest like cause pain on left side of chest under arm.

Bacterial infection also does the same in moist environment and results in pain and inflammation on the associated side and part.

Benign masses: Masses like lipoma, fibroadenoma or cysts in any structure in chest can result in pain in that area along with the armpit, like pain on left side of chest under arm due to lipoma which is pressurizing the nerves on left.


Some less common causes of pain on left side of chest under arm

Heart burn: When the acid from stomach travels back to the esophagus this can result in sharp chest pain and which less commonly travels to armpit likewise can cause pain on left side of chest under arm.

Anxiety: Any uneasiness alongside palpitations, sweating, and dizziness can be accompanied with chest pain and a tingling sensation in hands and arm and may less commonly involve armpit and may present as pain on left side of chest under arm or as a discomfort on right side or even both.



History taking, physical examination and basic imaging always form the basis of a good diagnosis. The intensity of pain as dull, achy is important for the doctor, duration of the pain and alleviating and aggravating factors, associated symptoms, any recent activity, weight loss, family history. All of these questions can definitely lead us to the diagnosis.

Physical examination may start with the vitals like blood pressure, respiratory rate, pulse rate and examination of redness, lumps, purulent secretions etc.

Neurological examinations can be done in areas like chest, arm areas around under arm.

Imaging like CT scan, MRI, and ultrasonography, echocardiography and ECG may be needed to complete the diagnosis and free the patient of his pain and worries. In some cases mammography may be requested like positive family history for breast cancer.


Treatment and prevention

Treatment may be as simple as the cause or as complex as is the cause and may involve some topical ointments, treating the underlying infection or heat, ice, rest in case of muscle strain. Avoiding any exacerbating factor like tight clothes can be seen as a part of treatment. When lymph node enlargement is seen as benign warm compresses might be recommended.

In case of angina due to any heart disease medication like statins, anti-hypertensive, anti-platelets and some cases a stent placement would be required and recommended.

Prevention may involve maintaining healthy weight, controlling diet, maintaining hygiene, getting screened annually after a certain age and getting vaccinated.


When to see a doctor?

When the pain doesn’t seem to get better and is associated with dizziness, breathlessness, and palpitations and if there is a lump or swelling growing painful, rash, any purulent discharge, recurrent infections or fever or any injury or trauma, a doctor should be consulted for thorough examination and some tests to avoid any serious damage and complication.



There are many a causes of pain on left side of chest under arm all of them can’t be attributed to some issue but can’t be overlooked as well to invite a big damage. In case any alarming symptom like painful lump in chest or armpit is felt it’s better to get examined by the doctor to get the benign causes ruled out and early diagnosis of some serious cause. Likewise anyone with concerned symptoms of angina and other associated symptoms should better run to their doctor.  So it’s better to consult the doctor if there is an interference of pain in your life or if you are really very worrisome about the condition.