I have the same thing! I've been seeking an answer for ever! It's the same UTI symptoms but never bacterial. I've had all the tests and dozens of urine cultures! Would love to know what it is. Also, no matter how much water I drink, my urine is still dark yellow (brown) and stinks. Not to mention the constant burning. Not even alieve or Tylenol helps with the pain. So glad to hear I'm not the only person with this problem. Doctors told me it could be due to constipation, but I haven't seen a correlation between the two.