SPINEPASS: SPINE Self-management Techniques for Persistent Headache After Concussion: Physical Therapy Targeting Autonomic and Dura Mater Function.

Inclusion Criteria: * Persistent Post-traumatic headache (PPTH) duration =or \> 4 weeks. * No self-reported improvement in headache pattern in the past 3 weeks. (Patients will be asked to determine whether the usual pattern of their headaches has changed for the better over the last 3 weeks. * Compass-31 score \> 21 to select patients who have evidence of ANS dysfunction which SPINEPASS aims to address. * Headache Impact Test (HIT6) =\>50 to capture headache-related disability of "some impact" or more. * Headache worst intensity \>3/10 on a numerical rating scale (NRS), at least once per week. Exclusion Criteria: * Contraindications for spinal or graded general exercise. * Contraindications to spinal manual therapy at or below C5-6 level * Cognitive impairment/ language barriers affecting ability to participate. * Redeployment/relocation or retirement planned within the next 6 months to reduce the chances of dropouts to treatment and follow-up. * Rating self-confidence to manage (eliminate and or lower) headaches without abortive medication at baseline of 30% or greater. * Inability to attend up to 12 in-person treatment sessions for 4 months. * Unwilling to limit commencement of other management for PPTH during the trial period. * Botox for headache management within the last 8 weeks or during the trial.