What kind of pain is it, exactly? One time I used scented shower gel from Victoria's Secret more days in a row than I normally do, and it made my nipples incredibly sore - almost to the point where I didn't want to wear clothing. Have you used any new soaps or perhaps a lotion? Is it both breasts?
If it's pain right AROUND the nipple area and not PMS related it could be caused by some type of breast trauma (like bumping into a hard or getting hit). Also, sometimes BC can cause breast pain around the nipples. If you haven't changed BC or experienced any form of trauma lately and are sure that the pain isn't caused from a nipple skin irritation (like from a soap), than if the pain continues I would get checked out by your doctor. Although uncommon, breast pain radiating from the nipple area can be a sign of cancer. Don't assume that since your young this couldn't be the case, either. Take care of yourself if you know for sure nothing else could be the cause.
Try taking an ibuprofen or aspirin in the mean time to ease the pain if it's really uncomfortable. You could also try limiting your caffeine intake. Sometimes this is connected to breast pain in women.
I hope you feel better soon! I know how much of a real pain that can be