It is very possible that the cause for your chronic headaches is the cervical osteoarthritis you already have.
Although, the main symptom of CO is neck pain, neck stiffness and shoulder pain, in some cases of degenerative cervical disease, a headaches can be the dominant symptom.
The headaches are usually suboccipital, starting at the back of the neck and radiating to the base of the neck and the vertex of the skull.
Actually, you may have a occipital neuralgia resulting from compression of the occipital nerve as it leaves the spine due to osteoarthritis.
Best wishes!
Marija