What could be a lump in your armpit if you mess with it swells and is irritable sore but leave alone goes down almost completely have had this for many years also feels like knot?

* Swollen lymph nodes: Lymph nodes are small, bean-shaped glands that are part of the body's immune system. They can become swollen in response to infection, inflammation, or cancer. If you have a swollen lymph node in your armpit, it may be due to an infection or injury in your arm, hand, or chest.

* Lipomas: Lipomas are benign, fatty tumors that can occur anywhere in the body. They are typically soft, movable, and painless. Lipomas can grow quite large, but they are not cancerous.

* Fibroadenomas: Fibroadenomas are benign, non-cancerous tumors that occur in the breast tissue. They are most common in women between the ages of 15 and 35. Fibroadenomas can feel like firm, round, or oval lumps in the breast or armpit.

* Breast cysts: Breast cysts are fluid-filled sacs that can develop in the breast tissue. They are usually benign, but they can sometimes cause pain or discomfort. Breast cysts can range in size from small to large.

* Abscesses: Abscesses are collections of pus that can form in the armpit due to infection. They are typically painful, swollen, and warm to the touch. Abscesses can be caused by a variety of factors, such as cuts, scrapes, or insect bites.

* Cancer: In rare cases, a lump in the armpit can be a sign of cancer. If you have a lump in your armpit that is hard, fixed, or growing quickly, it is important to see your doctor right away.

If you have a lump in your armpit, it is important to see your doctor to get a diagnosis. Your doctor may recommend imaging tests, such as an ultrasound or mammogram, to determine the cause of the lump.