Prostatitis, epididymitis, or even urethritis come to mind. You do not necessarily have to have discharge to go along with pain.
I would test the urine for bacteria and white blood cells, swab the urethra for gonorrhea and chlamydia. A thorough digital rectal exam should be done to evaluate for prostatitis. A scrotal ultrasound can be done to evaluate the epididymis. Prostatitis can certainly cause the pain and discomfort you are describing.
Non-infectious causes would include a hernia. Imaging studies such as a CT scan or ultrasound can be considered for further evaluation.
You may want to discuss these possibilities 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.
Medical Weblog:
kevinmd_b
**Note: I'll be away until August 14th - The forums will re-open then**