i know my one nipple is alway semi hard but i think thats because i use to have it pierced. i know a few people whos nipples are always hard, as far as i know nothng was found to be wrong.

Are you on any birth control? Because that might be the culprit....

no, im not on anything...its just really annoying because when i wear my bathing suit and stuff they kind of show through even if there is a little padding in it

They actually sell prosthetics now that make your nipples look hard all the time. Maybe you're just ahead of the game.

It's probably just hormonal fluctuations.... but I guess I'd bring it up at my next annual....