Causes
Cyclical breast pain (cyclical mastalgia) is very often associated with fibrocystic breast changes or duct ectasia and believed to be caused by aberrations in dynamic hormonal changes mainly involving prolactin response to thyrotropin. Some degree of cyclical breast tenderness is normal in the menstrual cycle, and is usually associated with menstruation and/or premenstrual syndrome (PMS).
Noncyclical breast pain has various causes and is harder to diagnose. Noncyclical pain has frequently its root cause outside the breast. Some degree of non-cyclical breast tenderness can normally be present due to hormonal changes in puberty (both in girls and boys), in menopause and during pregnancy. After pregnancy, breast pain can be caused by breastfeeding. Other causes of non-cyclical breast pain include alcoholism with liver damage (likely due to abnormal steroid metabolism), mastitis and medications such as digitalis, methyldopa (an antihypertensive), spironolactone, certain diuretics, oxymetholone (an anabolic steroid), and chlorpromazine (a typical antipsychotic). Also, shingles can cause a painful blistering rash on the skin of the breasts.
Read more about this topic: Mastodynia