I strained my neck one week ago - a car parked too close to mine and I had to contort myself to enter in my car. As I was trying to not hit my head on the door frame my neck went into hyperflexion, and I felt a sharp pain on the right side of my upper neck, behind the ear. I assume I strained a muscle and/or ligament.

I am fortunate enough that my PCS issues did not come back at full strength but I am having neck pain since then, very little range of motion, and my head is more sensitive to movement (e.g., walking).

I read a bit online on how to treat the strain. I thought that keeping a rigid posture would help and was even considering buying a neck brace but then I found this resource:
https://www.rcem.ac.uk/docs/Local%20...s,%202011).pdf

It says that stretching / range of motion exercises are very helpful to heal neck strains, and not harmful at all. I was a little surprised by this and wanted to ask if anyone had an informed opinion or experience on whether this is true, and whether these exercises can be started as early as one week after the injury.

Also, does a neck injury make the brain more vulnerable? I had become much less sensitive before this but I am now wondering whether I should avoid any jarring (from walking, car ride, or train ride) for a while, in case instability in the neck could make the jarring dangerous for the brain.

Thank you very much.