Have someone check your lateral profile. If your ear is in front of your humeral head. You have forward head posture. Chances are you have tight cervical extensors. Levator scapulae, splenius muscles group and as a result also tight subocipital groups. This can lead to headaches, trigger points and adhesion's throughout the muscle groups. I always check this when evaluating a neck/shoulder case in my practice in Grand Rapids. I also have them look to the ceiling. If they again can't get the ear behind the shoulder. The patient is in a for a lot of health problems stemming from the neck.
You can stretch the posterior neck like crazy and still not get the total desired results you want. Persistent back of the neck pain may still result. The problem is that even if you stretch like crazy, the neck still has to stabilize itself. So muscles are recruited that should not be. When the head is forward, those muscles that are tight are acting as guide wires and trying to pull the head back.
Enter the cervical flexors. The longus colli and longus capitus are two key muscles that lie on the front of the cervical vertebrae. These two muscles are notoriously turned off and weak. They help stabilize the neck. Without there activation the extensors are left to do to much work. If you have ever suffered a whiplash accident. These two muscles tend to be inhibited and weak.
One easy way to get these muscles back firing is the simple double chin exercise. Stand tall, and slowly retract the head so that it appears you have a double chin. Hold for two seconds and repeat for 20x, 2x a day. This will slowly start to turn these muscles back on and get them working for you.