Torticollis, also called wryneck, is a catchall term for any condition that causes the head to be pulled toward one side. It can be caused by a genetic abnormality, spasm, cervical misalignment or merely sleeping in an odd position. More serious, but rare, causes can be bone cancer in the spine which affects the motor and/or sensory neurons, infection of local lymph nodes or bone infections. The symptoms will vary depending on the cause and might include pain and stiffness.
As long as there is no underlying condition that would indicate contraindication, massage can be used for pain relief. The client's primary care physician should be consulted to get a specific diagnosis.