The causes of pain in the armpit with lumps mainly include the following: 1. Pain caused by sebaceous gland cyst infection in the armpit with lumps. The typical performance of a lump caused by sebaceous cyst infection is that the surface of the lump has a black head, squeezing the black head will have a white powder-like material overflow, the lump is mostly swollen and painful, the treatment method is to remove the sebaceous cyst and the cyst skin together. 2, caused by swollen and painful axillary lymph nodes, lymph nodes belong to the body’s immune organs, if the body’s axillary local or systemic inflammatory stimulation, causing the axillary part The lymph nodes are swollen and painful, leading to pain and lumps in the armpit. 3. Consider the axillary parametrial tissue hyperplasia caused by the parametrial is the formation of degenerative incomplete mammary gland development, if the parametrial development is more perfect, it will appear mammary hyperplasia as well as normal mammary gland, and can be clarified by performing breast ultrasound and axillary ultrasound examination.