nb19,

There is a condition called sub-concussive impact. It is a jarring of the brain that may or may not include any actual impact to the brain. I can give myself a concussion by shaking my head. Some brains are much more sensitive to movement that others. Prior concussions can create this extreme sensitivity to quick motion.

There are also neck injuries and strains that can cause concussion symptoms. There are neck muscles that connect to the skull above and behind the ears. These are frequently injured in whiplash like events. This may be your problem. The associated spasms can effect blood flow and other situations. Neck inflammation can effect vertebral blood flow.

Any cause of ischemia (lack of blood flow/oxygen to the brain) can cause concussion like symptoms.

So, to answer your question, No, you do not need to actually hit your head to suffer concussion symptoms.

My best to you.