I also get these feelings of having a new concussion or other PCS related symptoms from moving my head from one side to another really fast. (Had a couple of concussions in the past) I recommend you check out the concept of "Benign paroxysmal positional vertigo" aka BPPV which is essentially an imbalance of the balance center in your innerear. This causes massive feelings of dizziness, confusion and sometimes people throw up. Its often usual after a concussion/whiplash to get this and people stay in a constant PCS situation because the doctor has little experience with it and doesnt check for it. I myself is diagnosed with this as I have done tests to the eyes where you can see that my eyes are going from one side to another trying to find the balance when my head is tilted backwards and to one side. its my left inner ear which cause the problem. my right ear is ok. I didnt understand the logic behind this at first, but apparently there is many people going untreated by this. Google it and you will understand (I am new to the forum so cannot post links yet, sorry)