The thick blood vessels connecting the epididymis may hurt when pinched, which may be caused by certain diseases. Common diseases that cause such symptoms include varicocele, epididymitis and so on. 1. Varicocele: Varicocele refers to the abnormal expansion and tortuosity of the veins of the spermatic cord, which is usually asymptomatic, but when the condition is serious, it may cause swelling and pain on the affected side of the scrotum, and the symptoms can be relieved when lying down. 2. Epididymitis: Epididymitis is a common male disease, mainly refers to the inflammation of the epididymis. The main clinical symptoms are pain and swelling in the epididymis, and the epididymis becomes bigger and harder. In addition, there are many other reasons that can cause similar symptoms. When patients experience discomfort, they should go to the hospital immediately.