What Causes Pimple Like Bumps On The Areolas Of The Breast?

Hi, I'm 20 years old and I have pimple like on my aerolas. I read that it's a sign that I may be pregnant but I never had any sexual intercourse with my boyfriend. I had my period last April 23, 2011. It's really freaking me out. And I've been constipated. please help me.