Yeast infections

How do I know if I have a yeast infection? Lately I've been a little bit itchy down there. I just got off my period and when I wore a pad it just got so uncomfortable. And when I wore a tampon it hurt, and it usually never does.. Im just wondering how do I know I have one and who do I go to In order to find out? I'm 15 and prefer to not to tell me mom. I also have a boyfriend and he fingers me but I make him wash his hands before.