I am somewhat confused. Did you have a surgical fusion of C3-7 or did your neck auto-fuse? I will assume that you had a surgical fusion as auto-fusion has other connotations.
With a 4 level fusion of your neck over ten years with what I will assume is that of a normal and not sedentary lifestyle as there is concern of wearing out the levels above and below. This is not just from the fusion itself, but also from preexisting genetics of degenerative disc disease.
You probably have greater and/or lesser occipital neuralgia. The C2 and C3 nerve roots exit out from behind C1-2 and C2-3. These nerves run from the back of the skull over the head to the top of the eyes and around the ears. Nerve irritation will cause exactly the symptoms you describe.
You might find a physician that can perform facet blocks or nerve blocks. Rhizotomies might be an appropriate treatment if you get diagnostic relief from the facet blocks. Rarely, surgery might be indicated.
Dr. Corenman