I am almost 20 years old, Been STD tested and very healthy.?

I'm experiencing extreme pain during sex, like burning or ripping. I can't fully describe it. Its been going on for maybe 2 weeks now and I don't use condoms me and my boyfriend have been tested. I've been tested recently. Sometimes I can have sex with little to no pain. It feels like it's pulling during the times it's not burning. I'm cramping too along my hips sometimes painfully during sex. I thought maybe it was a yeast infection, I bought some of that cream and just finished it last night. But it's still painful down there. Does anyone know what it could be? Oh and it also burns when I pee if I don't drink too much water. And I know it's not a yeast infection or urinary track infection.�