The most common cause of these complaints is an inflammation of the prostate gland
or prostatitis. Too frequent or too infrequent ejaculation, sexual arousal without ejaculation, withdraw at the time of ejaculation, aggressive bike or horse back riding, and excessive spicy foods, alcohol, and caffeine in the diet can predispose you to this.
The other causes can be urethritis, epididymitis, urethral stricture, spinal problems and hernia. I suggest you a urologist’s evaluation.