Painful sex

Me and my boyfriend have been together almost 10 months, and have been having sex even longer. We used to have sex multiple times a day almost every day. I'm on the pill and was then too, but Recently the sex has gotten more painful. It's not a problem of wetness or attractiveness, but my vagina gets really swollen and hurts a lot afterward most of the time. It never used to! My boyfriend is pretty big and I'm wondering if it's just roughness? Anyone have any tips or suggestions?