Yes, I had one in my mid 20s.
I had been to the doctors about the constant urge to pee, even when only very small amounts. Bladder just constantly felt irritated. I suspected interstitial cystitis, or something along those lines.
Mine was done under general anaesthetic and the procedure itself was fine. However upon waking up was just told "couldn't see anything" and that was that.
I can remember crying with frustration as I was constantly in discomfort.
Years down the line, I've just lived with it.
I don't know what causes it.
I can remember a GP suggesting it was a psychological issue, rather than physical. I didn't even consider that at the time, as the physical discomfort was very intense. However there is no denying that it does get worse when I am stressed.
However, it did start around the time I became sexually active, at 18. Prior to that, I would pee around twice a day (!) with no issues. So I suspect some kind of infection.
I just don't know.