There is a powerful influence contributing to your headaches, neck and shoulder tension and you may have been ignoring her for many years; the Sternocleidomastoid. Named for her attachment sites, she originates at the sternum and medial portion of the clavicle, inserts at the mastoid process of 
the temporal bone and exists to among other things, flex and rotate the head and neck. The bilateral pair are readily visible, go to the mirror and take a deep breath, you can see the belly and proximal attachment of this graceful and commanding muscle.You can also begin to understand that when this muscle is hypertonic, it pulls the head and neck forward causing strain and imbalance.
Thoroughly addressing the SCM is often critical in resolving headaches, neck and shoulder pain, forward head posture (military neck), and even restricted respiration. Trigger Points in the SCM primarily refer pain into the head, jaw, and sternum, but can distress many functions including hearing, coordination, and vision.
Treating the SCM can be uncomfortable and even painful, but the results are off the charts! And while there are those who suggest stretching the SCM by tilting your neck from side to side, I find this can cause a lot of pressure; it fails to elongate the central fibers and aggravates the attachment points. I prefer tactilely stretching the muscle fibers specifically while working within my client’s tolerance to release tension and trigger points.
Make sure you request your trained and capable body worker to address this powerhousepair when you get your next massage!