Stiff enck causes
There are several muscles in the neck area and the ligaments over the cervical spine and the neck stiffness
can be from any of these .
The cervcial spine has discs and probelms wiht the disc themselves can cause the muscles around the neck to go into spasm as well. Auto accidents can cause this form the sudden jolt to the soine and the neck and upper back muscles. See you doc if it persists.