Prostatitis?

Patient: I have been having problems for well over a year now. I have been to multiple doctors and none have been able to pinpoint a cause or give a clear diagnosis. I have had many urine analysis tests as well as STD tests over the past 12-15 months at request of the doctors. All tests have come back normal. I have a history of kidney stones but this was ruled out in a recent X-ray.My day to day symptoms- Feeling as if there is something stuck in my urethra after voiding urine.- Stringy substance in urine when happening in conjunction with a bowel movement.- Annoying mild pelvic pain (this comes and goes)These symptoms come and go and I can’t seem to pinpoint what causes them to occur. I am a relatively healthy 21 year old. Drink plenty of water each day and stay away from soda.Part of me is wondering if this could be a prostate problem. The doctor I have been seeing has treated me with two 30 day courses of CIPRO in fear that it might be a prostate infection. Neither one of these courses of antibiotics has helped with the symptoms.I have begun to get very frustrated over this entire issue. Any help you can put forth would be greatly appreciated.

Symptoms: Feeling as if there is something stuck in my urethra after voiding urine.
– Stringy substance in urine when happening in conjunction with a bowel movement.
– Annoying mild pelvic pain (this comes and goes)

Doctor: