The most common cause of hard lumps in the chest at the age of 16 with pain when pressed is breast fibroadenoma, which is a benign tumor, mostly solitary, with good mobility and sliding sensation, slow growth, not increasing or shrinking with menstrual cycle, which can be observed clinically and treated with surgery if necessary. Breast cystic hyperplasia, caused by hormone imbalance, manifested as breast swelling and discomfort before menstruation, found a lump, swelling and pain after menstruation to reduce or disappear, the lump shrinks or disappears, can be clinically observed and regularly review the breast ultrasound. If the lump is accompanied by bloody nipple discharge, it is mostly intraductal papilloma. Due to the possibility of malignant transformation, early surgical treatment is needed. Breast sarcoma is relatively rare, mainly manifested by dilated veins visible on the skin surface, and early mastectomy should be performed after clear diagnosis. Breast cancer is very rare and should be treated with early surgery and postoperative chemotherapy.