<s>[INST] I have a bump under my left armpit, been there for over 3 years, its not big, and you cant notice it. When I press on it it is tender but otherwise doesnt bother me. Its not movable or anything its like its right in my tissue. What could this be? [/INST] Hi, dairy have gone through your question. I can understand your concern.  You may have enlarged axillary lymph node. It can be due to reactive hyperplasia, tuberculosis, lymphoma or metastatic carcinoma.  Or you may have lipoma cyst.  You shshould go for fine needle aspiration cytology or biopsy of that lump. It will give you exact diagnosis. Then you should take treatment accordingly. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using Chat Doctor. Wish you a very good health. </s>