If the testicle is painful on one side, it is recommended to go to the hospital for further examination to clarify the specific cause of the pain, the possible causes are as follows: 1. The testicular sphincter may be painful when the amount of sphincter fluid is large, and the scrotum is obviously enlarged when touched by hand, which can be identified by ultrasound examination of the testicle. 3. The testicle is fixed in position, with poor mobility and obvious pain when touched by hand, which is a relatively urgent situation, and if torsion is confirmed, surgical reset is needed.