Headaches can be caused by many different disorders and the upper facets of the cervical spine can be the cause of one of them. You can see a pain doctor (PM&R or anesthesia) to determine if these are causing your headaches.
The neck pain radiating down to your shoulder with your head in extension and lateral bending (“When I bend my neck back and to the left I can feel it in my shoulder blade area and down the left side arm”) is typical for foraminal stenosis. See the section on cervical radiculopathy for further understanding.
Squatting with weights is a very common exercise to compress the cervical and lumbar spines and cause premature degeneration.