I ended up having mine cut off surgically. If they bother you that much, you should do the same. Don't listen to these ignorant ***** who tell you that you need them. NO you don't ******* NEED them. You don't need them to feed your kids, because there is formula you can buy, and of course you don't need them for sex. Nipples are actually the most usless part on a woman's body. You can survive without them. Trust me I have for 5 years and absolutely love being nipple free. My husband loves my body as well.
but were you pregnant or ovulating?
I have this problem also...I just deal with it by wearing padded bras and/or these small adhesive cloths called Petals, which adhere to your nipples and really helps alleviate the problem. Other than that I dont worry about it.
Nipples can get hard for many reasons..arousal, ovulation, pregnancy, age, piercing(past or present)..it all depends..nothing to worry about..alot more would be happening if pregnant.
It's not exactly a sign of pregnancy, it's just a pretty common thing with women. I'm not sure what causes it exactly, probably slight hormone fluctuations. Sexual arousal will cause them to get hard too. I've never heard of this being a health issue, though it could be slightly embarrassing at times, but if they are constantly hard for no reason that you can see, I'd ask a doctor.