This neck exercise can help even if you have no neck pain. It is to remind you that you have a head-neck joint with 17 degrees of "nodding potential"
Stick your fingers in your ears and very slightly and very slowly nod your head. Keep your eyes open and interested. Lookin the direction of your next head tilt. Think of letting your head rotate around your fingers (your fingers don't nod-- only your head does.)
Face the mirror, stick your fingers in your ears, and nod. Keep eye contact with yourself.
Stand sideways on to your friend. Do the fingers in ears and the nodding. Ask your friend if you're nodding around your fingers, or from somewhere lower down on your neck. You should be nodding around your fingers, and your fingers shouldn't be moving as you nod.
For 2 minutes twice a day. But as often as you like.