Hi, it sounds like you have mastitis, inflammation of the breast and nipple. There are many etiologies for this, more commonly breast feeding, less commonly spontaneous infections as in your case. Sometimes trauma to the fat tissue in your breasts from seat belt acceleration-acceleration type injuries (car accidents) can cause fat tissue death and nipple discharge. Wearing really tight bras has been associated with fat tissue trauma and nipple discharge as well. I would recommend you get a full breast exam, possibly an ultrasound if you feel any lumps or the discharge becomes bloody, or you are above the age of 40 a routine annual mammogram for breast cancer screening. Antibiotics that cover skin flora like Penicillins (Keflex for example) are routinely given. If your breast feels warm to the touch, is tender, red and expressing purulent nipple discharge, you also may have a deeper abscess that requires surgical drainage. You should consult with a doctor for further evaluation to get appropriate treatment. Please follow up with the outcome and any further questions