So this is, like, really weird. My nipples become puffy out of nowhere. When it happens they get realy sensitive and tender. The puffyness will just go away if I bump in to anything or if anyhting touches them. I've read online, and it says that guys get it, but I'm a teenage girl. Its annoying becuase I cant wear sport bras becuase they stick out too much. Even if I'm going to workout, I have to wear a paded bra. It doesn't happen in certain conditions or anything, its just random. It has been happening for about 1 1/2 to 2 years.