Burning during sex

Hey ladies! Lately, I’ve been experiencing burning during sex and it’s keeping me from finishing. I went to the gyno and told her that it burns and that it also burns when I try to put in a tampon on my period. She said I might have a yeast infection but I haven’t had crazy discharge or burning while peeing. I peed in a cup and she said everything looked fine from my results. I’m not sure if the test picks up on STDs. I’ve only had one partner in my life, but his ex was a skank. Does anyone else experience this?