Hello dear. I guess your younger brother had operation for torsion of testes. Pain in the testes can be due to several reasons 1. Torsion of testes. It is a condition where there will be sudden, acute pain in the testes. The testes looks inflammed, red, very tender to touch. even slight movements of the testes creates lot of pain. Its a medical emergency where the doctor will perform surgery and correct it. If it is delayed for long time, the testes may get necrosed due to blockage of blood supply 2. Epidydymo-orchitis. Its infection of epidydymis (a chord above the testes) and testes. This condition can be treated with antibiotics and pain killers. Sometimes intravenous antibiotics may be required One simple test to differentiate between torsion of testes and epidydymo-orchitis. In torsion if you elevate your scrotum there will be acute pain, whereas in epidydymitis if you do so, there will be relief of pain 3. Varicocele. This is a condition where there will be dilatation of veins above testes. If severe surgical removal is necessary Kindly consult your doctor. He may advice you to undergo Ultrasonography of scrotum which will tell the diagnosis. Hope i have answered your question. Feel free to contact me if you have any more questions. I ll be glad to help you. All the best With warm regards Dr Sanjay Kini