Orchitis is an inflammation of the testicles. It can be caused by either bacteria or a virus. Both testicles may be affected by orchitis at the same time. However, the symptoms usually appear in just one testicle. Ultrasound imaging can rule out testicular torsion. Testicular torsion is another condition that causes extreme pain in the testicles and groin area, and the symptoms are often confused with those of orchitis. Testicular torsion is the twisting of the spermatic cord — a network of nerves and blood vessels that runs into each testicle. It can threaten your fertility if it interrupts blood flow to your testicles. Therefore, you should see a physician immediately. a spermatocele, which is a fluid-filled cyst on the ducts of your testicle a varicocele, which is an enlarged vein in the spermatic cord of your testicle