Is cracking your back and neck bad? I read it's air bubbles between joints that crack...

I was told that the cracking is soft tissue/ligaments, not the bones. The cracking is loosening them up and it isn't particularly bad. However jerking your head or neck around to make it crack is not advisable as you can do damage. I heard of a masseuse who tried that on a client and broke her neck, I do wonder if you can break your own neck.