The one thing that helps me when I have a stiff neck is an exercise I learned. Sit on a firm chair with feet firmly on the floor, and back straight. Turn your head to your right shoulder as thought trying to touch your chin to it, hold it there to a slow count of 10. Slowly move your head back to the center and lower your chin to your chest to the count of 10. Then repeat to the other shoulder. Usually 3 of these work for me. This also eases a minor stiff back or shoulders.