I’ve found this stretch very effective to relieve constant pain in the neck. And moreover, it is so easy to do.
What this stretch does, is increase the range of motion in the suboccipital triangle and suboccipital muscle group.
Deep suboccipital rotation
Go down to all fours, keep your neck neutral and look at the floor.
Perform small movements of rotation with your neck, rotating your neck no more than two inches each side.
Upper back stretch with isometric hold
This isometric stretch exercise aims at stretching / relaxing the upper back muscles.
When the upper back muscles are tense, they cause stress and a series of muscle and joint pain in the upper part of the body: neck muscles being in the way, they find themselves strained, causing neck pain, sore neck, and headaches (tension headaches) that can be permanent.
One of the treatments offered by isometric physiotherapist is to apply a force to the arms on an object that does not move (in the video, the coach uses a foam roller), but can be any stable object located at a height a meter.
Kneel facing the object, pressed down with the arms, put the head between the arms and apply isometric stretch by trying to raise the upper back while with the arms, resist so that it requires an effort to go up with your upper back.
The isometric contraction should last 30 seconds to be effective.
Do this stretch as much as you want (unless it hurts of course), and be sure to take a good pause between two stretches.