Possible causes would be infection (STD or epididymitis) as well as the various causes of scrotal masses, which can include a cyst, hydrocele, varicocele, or cancer.
I would obtain urine tests or a urethral swab to evaluate for possible infection ot STDs as well as a scrotal ultrasound. The ultrasound would be able to determine any of the scrotal masses listed above.
These options should be discussed with your personal physician or urologist.
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