Doctors say sometimes vasectomy can cause permanent pains in testicles. how common is this?

Rare complication: Chronic testicular pain is a rare complication after vasectomy. Find a urologist with a lot of experience doing vasectomies and who does open-ended vasectomy. "open-ended" vasectomy, in which the testicular end of the vas is not obstructed, has less risk of causing congestive epididymitis, believed to the most common cause of post-vasectomy pain syndrome.

VERY RARE: Very uncommon. I have one of the world’s largest experience in treating post-vasectomy pain and with that, I have performed 50 reversals specifically for pain in the last decade. 500, 000 men have vasectomies every year. Very few experience long term pain.