Is neck OA like hip OA? When I walk a lot, my hip stiffness eases. What exercise can I do to improve neck/upper back tightness?

Heat/stretch. The best way to stretch your neck and upper back is to get the muscle warm with a heating pad or warm shower then do gentle stretches through the range of motion of the muscles. Hold each stretch for one minute. Doing yoga is also a great way to stretch out the muscles.