Gynecomastia can be categorized into physiological and pathological according to the cause. Physiological swelling and pain is generally not important, while pathological breast swelling and pain is more serious, should be timely medical treatment. Physiological causes of gynecomastia include pubertal breast development, irregular work and rest, emotional changes, emotional changes include excessive anxiety, fear, anger. Physiological swelling pain is generally mild, no cycle, this situation is not very important, can be relieved on their own. Pathological breast swelling and pain include follicular abscess, acute breast abscess, mammary fat necrosis, breast cancer, etc. Symptoms are more obvious, the pain is persistent and intense, sometimes accompanied by fever, tenderness, etc. This situation is more serious and needs to go to the hospital. This is a more serious case, and it is necessary to go to the hospital for examination, such as breast ultrasound, blood routine, etc., to clarify the cause of the disease and treatment. Glandular follicular abscess manifests as abscess around the periphery of the glandular follicle, with tenderness, mostly accompanied by fever; acute breast abscess is limited to pain, the lump has fluctuating sensation, also accompanied by fever, chills, etc.; fat necrosis of the mammary glands has breast pain and tenderness, most of them have history of mammary trauma, accompanied by redness and swelling of the skin and ecchymosis, etc.; a small portion of male breast cancer patients can also be manifested as breast swelling and pain. Therefore, men with breast swelling and pain should consult the doctor in time, and follow the doctor’s instruction to standardize the treatment after finding out the cause, so as to avoid delaying the condition.