Is there a family member that you can talk to about it? If there isn't and you want someone to look at it, ask the school nurse. She could probably take a look and tell you whether or not she thinks you should see a doctor. You should tell your folks or gaurdians so that they can take you for a checkup. It could be some sort of infection. If you run when you are wearing a tight shirt, the clothes can rub on your nipple and irritate it and make it hurt. Or if you are sweating and running or playing sports, the nipple can rub and get kind of raw. If you squeze the nipple, does any thing come out of it? How long has it hurt? How long did the other nipple hurt? The doctor will probably ask you that stuff. He/she will also probably feel your chest area to make sure there are no lumps and bumps. You are probably ok, but have someone take you to a doctor just to make sure. Good luck.
Hi,
Well the pain could be due to tight clothing or dryness of skin or trauma due to friction or rubbing against a hard surface. Just put some soothing lotion like calamine and a moisturising lotion and see if that helps. If the pain still persists get a clinical evaluation done by your physician. You have not mentioned your age and gender and how long the pain has been there. Is there any associated nipple discharge? Consult a physician to rule out a infection and to see if you need to take any antibiotics or not.