What Causes Itching And Soreness In Vagina After Sex?

ive been sexually active since i was sixteen. I am eighteen and now i am with my boyfriend. lately every time we have sex I get really itchy like an inch inside my vagina, towards the front of my body(anterior side). I used at home treatments for yeast infections which helped, but it kept coming back. now, i have sore pain in my vagina. its like, right at the opening but still inside, and kind of closer to the anus. i dont know what it is or how to help it stop hurting.