The Multiple Causes Of Pain Under Your Armpit

Pain under the armpit can be due to a number of things, most of which are not serious, even if the pain itself is quite bothersome. There are a few diseases and disorders however that are serious in nature that have pain under armpit as a symptom. If the pain is particularly severe, has come on suddenly,    seems to be steadily getting worse, or simply won't go away, it's a good idea to seek medical attention at the earliest opportunity.

Infections And Swollen Glands

Very often, pain under armpit is due either to an infection or to glandular swelling. The armpit, being a warm, dark area, which can also be rather moist at times, makes a nice breeding ground for bacteria. Because of this, the slightest wound or scratch can easily become infected, and may become be a cause of some pain. Cuts produced when shaving hair from under the armpit are a frequent cause of infection and pain, though the infections seldom become serious. Swollen lymph nodes are another cause of pain in the armpit area. Swollen lymph nodes occur when the immune system produces white blood cells in response to an infection in the body. This swelling can either be localized or systemic. With respect to the armpit, it is usually localized, and is usually in response to an infection in the armpit itself or in an adjacent area. Swollen lymph nodes in the armpit area can be quite uncomfortable, but they usually last only a few days at most. Something like a common cold can cause systematic lymph node swelling, which at times might include armpit's lymph nodes. The armpit is among those parts of the body where aches or pains can be experienced during a viral infection.

Cysts Or Boils

The skin under the armpit is much more sensitive than the skin covering most other places on our body, and as such is more easily irritated. Skin irritations can lead to the formation of cysts or boils, and the latter can often be extremely painful and tender to the touch. Cysts can be painful as well, especially in an area where the skin is as sensitive as it is in the armpit. Cysts are usually quite harmless, and are also easily dealt with. A cyst may be removed if it is being quite bothersome, or it may be left alone, though it may be monitored occasionally in case it shows any signs of growth.

Muscle Strain

Armpit pain isn't always due to an infection, nor is it always symptomatic of a disease or illness. Pain under armpit can also be the result of a muscle strain. A muscle strain affecting the armpit is usually the result of throwing something, or forcefully swinging at something, as one would do in baseball, tennis, or even golf. Javelin throwers who have not warmed up properly often will experience armpit pain as a result. A pulled muscle can cause a great deal of pain in the armpit. The pectoralis muscle often is the usual culprit in this case.


Women who are breastfeeding will on occasion suffer pain under armpit as one of the symptoms of a condition known as mastitis. Mastitis is an inflammation of the breast tissue. It is the result of an infection, which in turn is caused by bacteria having entered a cracked nipple. Mastitis, should it occur, usually happens several weeks after childbirth. An area of the breast will often become quite painful. Pain may be experienced under the armpit as well, though it tends to be the less severe than the breast pain. Mastitis is usually treated with antibiotics. Neither the infection nor the treatment places a nursing baby at risk.


A lump under the armpit can also cause a great deal of pain. A lump is not the same as a swollen gland. It tends to be more firm, and also more permanent. A lump under the armpit is one of the symptoms of cancer, and should always be examined by a physician. A lump does not mean that cancer exists, but nevertheless the presence of one should never be ignored. One reason for having a lump examined is because one that can be felt or is causing pain or discomfort probably has been there quite some time, but was simply too small to be noticed in the past. The pain from an armpit lump can sometimes be quite severe, even if the lump itself is too small to be felt. For that reason, any severe underarm pain should be brought to the attention of a doctor post haste, since the possibility of cancer is very real indeed.

It just makes sense that if a pain in armpit or anywhere else in the body persists, is sudden and severe, or becomes steadily worse over time, it should be looked into by a doctor, as all three situations are abnormal. The underlying cause might not necessarily be anything serious, but in any event, it is always good to find the cause, so that the condition can be effectively treated.