Warm/buring sensation when peeing or erection but passed three urine tests and the doctors doesn't know what is the cause.does anyone have a idea?

Spices?: If you eat even a few of those hot little peppers, you can end up with urethral burning. Could this be the explanation?

Burning urination: patients with urinary tract infection may present with burning upon urination, frequency and possible blood in the urine; a urinalysis may show bacteria, white blood cells and nitrite; However, a urine test may not show any bacteria if the infection is due to uroplasma/mycoplasma, also infection with Chlamydia would not show bacteria either in the urine, may need to see a urology for evaluation