Help!! So much pain!

Sam
Okay so my boyfriend and I haven't had sex but are planning to so we've been trying to get my body warmed up since I'm super tight haha. Last time my BF tried to finger me he couldn't even get his finger in because as soon as he tried to go in it hurt SO BAD! I shreiked!! It was almost like a stinging pain. Since then I've been trying to do it myself and it hurts really bad to first enter my vagina but once it's fully in it doesn't hurt. Does anyone know what I can do for this or what this is??? Thanks!!