Pain when bf slips dick in

So every time when my boyfriend slips his dick into me, it hurts. Not a drastic amount but I feel like a tight pinch for like a minute and then it goes away. He has a big dick tho (tmi sorry) but I was wondering if maybe that’s why I feel some kind of pain? He’s my first sexual partner but hes seriously very big so idk if maybe it just takes getting used to