What are the causes of soreness in the nipples?

I enjoy some discomfort surrounded by my nipples and I be wondering what the cause could be.
Me and my hubby are trying to concieve, but I took a pregnancy testing 2 weeks ago & it be denial.
what could be up?
Answers:

After getting past its sell-by date the Depo 6 months ago I still haven't have my spell!?

hormones, trauma, piercing, biting, pinching, too small bra, etc. if you are concerned, bid your gyn.

I might see a gynecologist ?

Maybe you are pregnant, go and get tested again

Left side hip and belly dull agony what is this from>?

I surmise you should see a doctor. If not, perchance research your symtoms online.

Is it out of danger to filch One a Day multivitamins and Vitamin E together in in the future?

If you a moment ago have your time of year or it is earlier. No worries. It's PMS. I am sure. =] If this isn't a intuitive occurance consequently I'm sorry. I don't know.