There are three types of cervical sitting supports.
U-shaped neck cushions are used for snoozing travelers on airplanes, trains, and cars, and for reading in bed. However, they are too constricting, and perhaps even dangerous, for use when driving or working at a desk.
Half-rolls are better for driving and desk work. By the way, these are the same half-rolls used for lumbar support.
Counterbalance devices (i.e., "Bodyrite Posture Pleaser") lessen loads through the neck and thoracic areas during active reaching work.