Slight burn in tip of penis

Hi,
So I had sex with this girl, condom broke, then I put on a new one about 3 months ago. Afterwards, I cleaned my penis, even putting a little soap in my urethra. The next day it started burning slightly when I pee. Over the course of the next 3 months, the slight burn was on and off. I got tested a few days ago for STDs, UTIs and other bacterial infections and everything came back negative. I went to see a urologist who says there is absolutely nothing and that's it's probably psychological but I'm a little confused since it still does burn when I pee.

The more I drink, the less it hurts but I end up going to the bathroom every 30 mins... Also it doesn't burn when I have sex/masturbate. I tried to eat cranberry pills, doesn't do much. Tried to clean up with iodine after I pee, doesn't help. It also seems to hurt less if I pee after pulling my foreskin (I'm not circumcised) but before this started I would never bother to do so to pee.

Anyone has had my condition before? Help much appreciated.