“Craning” the neck to look upward toward a TV or computer monitor, or tilting the head backward to see a monitor through the near-focus part of bifocals, is a common cause of headache.
This posture causes the occiput (the bone across the back of the head, just above the spine) to be stressed inferiorly. This inferiority may be more on one side or the other (unilateral) or global (bilateral).
When I see this in patients in my office, it is often in combination with a superiority of the back part of the second cervical vertebra, which makes the headache even worse.
My Activator Chiropractic Method has focused, precise adjustments that correct the problems without discomfort to the patient, and I offer ergonomic counseling to keep it from happening again.