My and testicles retract after pulling on it severly.?

After pulling on my to make it bigger, my testicles retracted into inguinal c. Now my testicles retract for no reason, I could be driving and I could feel my testicles retract and after I , my testicles go all the way into the c. Pulling on my obviously damaged my and testicles. I went to a urologist and he said everything was normal, I know this is not normal. Should I get an ultrasound to see if there is something damaged inside my groin/testes?