Possible delayed pain due to the neck strain?

Expert PT should be helpful to find reasons for the muscle/neck and some of the head issues.
Muscles in spasm can clamp down on your arteries & veins..
You can have lingering neck pain that goes unnoticed until something trigger a flare up..because it slowly sneaks up on us..

Trigger points can be a factor also, many sites online with interactive charts to see if they might apply.
samples -
Pain Reference Chart
Head and Neck | The Trigger Point & Referred Pain Guide