Torticollis is a condition where a joint or disk is injured and you can't move your neck. Sometimes the head is bent or turned a little to one side, and sometimes it's straight but can barely move in any direction. This type of problem is usually caused by a disk injury. Whiplash can cause this condition, or it can come on by sleeping in an awkward manner.
The spine is meant to move a lot, especially the neck. This is so we can quickly look around, above, and below in response to the environment. When the spine cannot be moved without intense pain, it's a sign of both a joint and nerve problem. The nerve may be pinched or compressed, stretched, or irritated by chemicals from inflammation/swelling. To protect the nerve, the body puts a splint on it in the form of muscle spasms. This is what can keep you from moving your head.
If the joint injury is reduced by aligning the bones of the spine, the healing and scar tissue will stabilize the area in alignment. If the joint is left out of alignment or is hypermobile, this can lead to future degeneration. To get the joint moving and functioning normally again, you need to have motion through the joint adjustment, and exercises to keep activated. One study showed that patients who wear foam collars after whiplash do worse than patients who were actively mobilized without collars. It may at first seem counterintuitive to move when pain is there, but it's all about moving within your pain tolerances. Instead, many patients wear collars or do not move their neck enough. This causes the muscles to become more inflexible and contracted. Over time, it can lead to substantial weakness and even atrophy (wasting away).
So, even in the early stages of a whiplash injury, when the neck can barely move at all, small movements that are not painful are encouraged. Specific chiropractic adjustments will reduce the irritation to the nerve that is signaling the muscles to spasm. Once the nerve is freed, then the muscle will usually release. Greater ranges of movement will follow as the body allows. This should not be hurried because the nerve and disk is at risk for re-injury in the very early stages of healing.
Medications and surgery will not correct the alignment of the spine. When a joint is sprained, it needs to be re-aligned to reduce the tension on the ligaments and disk. Your doctor of chiropractic can guide you through this process so the range of motion returns quickly.