Painful but not swollen breasts can be caused by mastitis or breast cancer or mastopexy. Mastitis is most common in breastfeeding women and is mainly caused by the presence of lumps and hard nodules in the breast and an increase in surface skin temperature as well as an increase in systemic temperature. Anti-infection treatment is required if necessary, usually intravenous penicillin or cefothiamidine, and the milk should be emptied and treated symptomatically. If there is a lump inside the breast, which is suspected to be breast cancer, it can also lead to pain in the breast and should be further clarified by breast ultrasound or mammography. If there is no lump inside the breast, it may be caused by hyperplasia, which is a benign lesion, and can be treated symptomatically with oral medication, such as prozac or breast disease.