Cervical Dystonia

Overview
Cervical dystonia is also known as spasmodic torticollis.  Dystonia occurs when opposing muscles are contracting simultaneously, causing twisting movements and awkward posture of the head and neck.  The movements may be sustained, jerky, or a combination.  Spasms in the muscles or pinched nerves in the neck can result in considerable pain and discomfort.

Symptoms
Involuntary contraction of neck muscles
Abnormal postures of the head and neck
Jerky head movements

Causes
Genetics
Trauma

Diagnosis
Physical examination

Treatment
Injections
Anticholingeric or dopaninergic drugs
Surgery
Physical therapy

Source: https://dystonia-foundation.org/