Why does my neck crack exactly?

Joint surfaces move: Cracking a joint moves the parts of the joint, with the cracking noise coming from cartilage surfaces sliding, from movement of a little air-space from one place in the joint to another, or from some other non-traumatic event. A person with no joint pains before or after cracking a joint is probably not damaging the joint. A doctor should evaluate any pain or stiffness associated with cracking.

Couple of answers: There are a couple of things that can go on with neck cracking. One is that the tendons of the muscles of the neck snap over each other and the other is that the joints of the neck called facet joints can produce a popping sound as well. Neck cracking during regular movement is very common and benign. I do not advocate people violently cracking their neck by forcefully twisting their neck.