Nobody can say how much impact force or jarring it takes to cause another concussion. In fact, sub-concussive impacts can be very damaging to a concussed brain. Try to not be paranoid about your head. Instead, try to practice safer movements. I do not turn my head quickly but instead turn at the shoulders. This slows the movement. I also do not shake my head NO.

Startle movements can cause problems from both the quick movement and also from the spike in blood pressure and rise in adrenaline.

Somebody wrote about how their daughter use Neuro Optimization, I think, to help with head aches. I am not vouching for it but it helped her.

My best to you.