Hi Dan,

it is very possible that the extreme sensitivity on top of your head giving you the sensation that your brain shakes , is actually coming from your neck.

Indeed he first two upper vertebrae (C1-C2)are often involved in post concussion syndrome mimicking /adding to the actual symptoms of head injury -often giving headaches and even vertigo.

Do a Google research "occipital neuralgia" you might recognise your symtoms.

An experienced, careful chiropractor would be able to evaluate and treat you with this condition.

Do not despair. There is always a solution.
Pepa