Infection should be completely ruled out - including tests for STDs and urine tests looking for a UTI.
The prostate should also be carefully examined looking for prostatitis. A digital rectal exam as well as a transrectal ultrasound can evaluate for abscess or infection.
If infection is not the cause, anatomical issues like a urethral stricture or polyp can be considered. A cystoscopy is the most comprehensive test to evaluate this.
Metabolic disease like thyroid dysfunction, diabetes and B-12 deficiency can also be possible and tested for.
You can discuss these options with your personal physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
kevinmd_b