What could be causing vaginal pain and even the pain during sex?

awww poor tiny yng lil teen noooo. heheh even though u grls walk by me with your heads down and i can completely see your eyes tirn to look atmy bulge lol heheh. but ok lets see. like are you talking about the sides being sore, or does it feel more like the bottom sides and top are inflamed?
its not itching is it?

lmao the check to verify I'm human just randomly happened to be bigger lol

Ew, dont be a creep

There can be many reasons for pain during sex. If you are not using protection i would suggest not having sex until you figure out the problem. If you arent using protection you need to get tested. And see your gyno yearly.
Maybe there isnt enough lubrication, maybe youre allergic to sperm if your face hurts after(and yes its very possible to be allergic to sperm) maybe you get air trapped inside(which causes pain and pressure on your urethera(pee hole) its too vague to know. If you are going go have sex just be safe, our vaginas are a fragile ecosystem, many things can throw it off, ao youre being safe, using proper lubrication, and protection. Not all STDs and STIs are visiable. Some can be in your body for years without showing up, which is why getting tested is important and using condoms!
Be safe!♡