Not sure, hun. You'd need to go back to another doctor. Sounds like it could be deep within your urethra instead of your bladder, especially since you say it happens after you get off, and men have urethral spasms when that happens. A urologist would need to address the problem. That deep pain/burning problem also happens when you have a kidney stone that's moved along the urinary tract and is hurting you. But that's not usually something that's after-sex connected.

Can you connect it with any other incident? Like maybe it happens when you might be dehydrated? Or when you've used specific substances of some kind?