I frequently discuss upper neck injuries and the need to have good sleeping posture to allow the ligaments to heal and tighten up. Unstable upper cervical vertebra can cause chronic inflammation that exacerbates concussion symptoms. I have been living with this issue for 14 years.

Others frequently have used upper cervical therapies to resolve this issue.

btw, A few good days is just a start at recovery. Hopefully, these improvements will be lasting.