Is It Normal To Have The Testicles Twisted Without Any Pain?

Hi there, bit nervous about asking this.
I went to the doctor a few years ago when i was about 14, tellin him how my testicles seem to move freely as there is no pain when they twist bout 180 degrees - i told him how i had twisted it and he said if i had done anything id know, ive found it did it on its own rarely, is there any concern or am i normal, im 18 i have a healthy sex life im just worried sick about it.

Thankyou :)