Sex Question

Kourtney
So I have a question 
what does it mean when ur man enters your vagina and it burns and hurts? 
I've already gotten a Pap smear early in this month seen my ob gyn and was told I'm all good down there and I may have signs of yeast infection and I was given 1 pill for it and so now it's gone  and I'm all good and healthy 
but I don't understand why sometimes especially when we do it too much or even at certain angles that it hurts and burns when he enters my vagina.
Any ideas?