Why is my vagina burning on the outside?

Ok I know I don't have an std I got tested. I went to the dr and she gave me antibiotics and meds. It went away while I was on the meds. It came back. I went back and she tested my urine again and I don't have any infections anymore. It is still kinda burning on the outside. It doesn't hurt at all when I pee nor do I have trouble peeing. What the hell is going on?! Its mild but very annoying! No blood when I pee or cloudy or anything like that either.