im becoming really sore after having sex?!

basically, it is as the title says. after i have sex with boyfriend, or sometimes during we have to stop because im getting too sore and sensitive down there. i normally find that if i go to the toilet after, it stings a little to pee, and this will happen like a maximum of two times. after this, i am fine just a little bit swollen still. the next day i always seem to be fairly better, but i don't understand what is causing me the pain?

i am on the pill, so we do not use a condom, as a find a condom actually hurts all the more. i know it may sound a bit too in depth aswell, but me and my boyfriend thought as we dont have sex alot and i am still quite tight, when we do that might be why? but im oblivious to any other reason.

help would be much appreciated :) thankyou.