I assume since this is posted in pregnancy you are not currently nursing - During pregnancy my breasts and nipples just really hurt and nothing seemed to help - it should pass. If there is no reason for them to hurt (i.e. nursing) then I don't really think there is much you can do. Maybe a hot shower or hot compresses would help. Hope you feel better soon!
You could try putting Lanolin on, it won't hurt and might help. It's sold in the baby section with the other nursing stuff. There are also these gel pads you can get, and you can put them in the fridge to get them cool and then stick them in your bra. They really helped me when I first started nursing. The cold on your nipples might help. Good luck, I hope you find some relief.