Sit, stand or lie on you back with arms at your sides
Side bend- (laterally flex) the head to one side and tip the ear to the opposite shoulder in a pain free range of movement
With the opposite hand, slowly begin shrugging (lifting the shoulder towards the ear) and hold for 15 seconds then lower the shoulder to the floor.
Repeat the exact same neck exercise on the opposite side. It’s best to try and do 2 sets of 15 seconds each side at least twice each day but there’s no real sensible limit so it can be done as often as you can fit it in.