As we discussed earlier, the epididymis is a tightly coiled tube located in the back of each testicle. It stores your semen and helps deliver it when needed. If you're feeling a pain in your testicles, there's a chance it's caused by a cyst -- a spermatocele -- growing inside the epididymis.
The cyst is benign, and it started out as accumulated sperm cells. It forms at the head of the epididymis, though these cysts can develop on the testicle or along the vas deferens. Spermatoceles are often found during procedures for other issues, and they're thought to be pretty common. Most of the time, they're very small and don't cause any problems. Sometimes, however, they grow to the size of several centimeters, and at this point, you may feel a sense of heaviness in your testicles, discomfort or even pain.
Most of the time, spermatoceles require no medical treatment. The doctor will want to periodically check it to make sure it's not growing, and to verify that it's not cancerous. However, if it's causing you any kind of suffering, you may be prescribed antibiotics. In extreme cases, the spermatocele can be removed, though there is significant risk that the patient will lose the ability to father children as a result.