If you have a hard lump in your armpit, you should further combine it with color ultrasound examination of the armpit, which is commonly caused by enlarged lymph nodes in the armpit; in elderly patients, it is commonly caused by breast tumors, which manifest as painless lumps in the breast and abnormal changes in the nipple skin, nipple overflow, etc. It is more likely to be a malignant tumor of the breast, and it is also easy to have axillary lymph node metastasis, which requires further mammography. Some patients may have secondary lymph node enlargement after mammary gland hyperplasia; strain and trauma may also lead to local soft tissue contusion and painful aseptic inflammation of axillary lymph nodes, which can be treated by physiotherapy with hot compresses.