Why does my side right boob hurt?im not on my period. i wasn't wearing a bra, i'm a size 28c. my back doesn't hurt.

While it may seem: surprising, localized areas in the breast may be painful, usually due to fibroglandular breast changes (colloquially called fibrocystic disease), at some point during the menstrual cycle, usually a few days before the expected period but not always. Wearing a supportive bra and taking acetaminophen/ibuprofen may help. Check for unusual lumps and report anything worrisome to your doctor. Stay well.