Over the past two months, I have been suffering from a horrible bladder infection which was very resistant to three forms of antibiotics. It then turned into a yeast infection which is apparently now clear. I had sex for the first time since and had a terrible burning sensation. Last week I had a urine sample and pap smear... I have no signs of UTI, yeast infection or STD. What would cause this sensation? It burns so much it feels like someone is rubbing sand paper all up inside me!