Neck and upper back pain and stiffness can be localised, but may also radiate (spread) to the head causing headaches (cervicogenic headaches), or to the upper back, shoulders and arms/hands. Symptoms include pain, 'pins and needles', numbness or weakness.
In clinic I often find that neck issues are due to postural compensations for issues lower down in the body, resulting in over use of some muscles of the neck and a reduction in range of movement of the upper back and neck. They may be due to lifestyle factors, like many hours working at a desk with poor posture, driving and even stress.
Ache type pain often then results from the muscle fatigue/overuse or the strain around the upper back/neck (often with a visible 'sharp bend' at the base of the neck). Sudden, sharper pain – often causing the neck to seize up or reduce the ability to move (e.g. being unable to look over one shoulder) – is often caused by irritation of the neck joints (facet joints) or by the upper ribs. The body can respond by 'locking down' the area to prevent movement and further irritation of the joints.
Headaches (cervicogenic) and Thoracic outlet syndrome
Tight muscles around the neck often press on the nerves of the top of the head (causing cervicogenic headaches), or the nerves into the arms (causing 'pins and needles'/numbness/weakness) in the thoracic outlet area (the area to the side of the neck and behind/under the collar bone). This is known as 'Thoracic Outlet Syndrome'.