Need examination by urologist. Most probably it is arising from rail of epididymis. May require scrotal ultrasound and FNAC to confirm nature.

Hi...., there are various causes for testicular pain.... Pain may originate in the testicle or nearby parts of the reproductive tract, or it may be caused by a problem elsewhere in the abdomen, such as kidney stones or a hernia. The testicles are very sensitive to injury, and pain may be caused by even a mild blow to these organs. Infections or inflammatory conditions can also cause testicular pain....Consult urologist for further evaluation....