Hi and welcome to HCM. Thank you for your query.
It is hard to know exact diagnosis without some tests. Most commonly it can be casued by infection, prosattitis or epididimitis. ALso
STD should be considered.SO do urethral swab test and urine analysis. Some more serious diagnosis such as tumours should be ruled out with testicle
ultrasound. This would evaluate
prostate enlargement too. Wish you good health.