Pain down there

First of all, I am a virgin. After almost every time my boyfriend fingers me i have some redness down there and when I pee it annoys me. But this doesn't last long, I feel it for like 2 days and then it is normal again. What is this? Some of my friends told me because im vergin every time something enters it opens a little bit so this is why it hurts. I don't now. Can someone tell me?