Burning Pain While Peeing

Ever since January, sex has been painful with my boyfriend. He was a virgin and I had been tested for STD's before and had come back clean. I was treated for a yeast infection even though tests came back negative. I saw a gyno and she said that the side of my vagina had been bruised (but we weren't having rough sex). We tried again and it didn't hurt as bad. 
Fast forward to now, it still hurts sometimes to have sex, and now, afterwards, it really hurts from to urinate, and the pain lasts for hours afterwards, it feels like it is coming from my urethra, and the pain radiates down to my legs. 
I've been tested negative for a UTI and I don't have any STD's and the doctors that I've been seeing can't future this out. Does anyone else have any of these symptoms?