Google psychosomatic pain, also known as psychogenic pain. There is plenty of information. You already have the foundation for it with your anxiety struggles about impacting your head.

It is amazing what the mind can do that goes against all logic. I've been through enough of these time when the mind tries to say something that is not real.

I have memories of events where I came very close to very traumatic events. I can feel the full effect of that event even years later when I am reminded of it. I can feel pain just seeing a head impact on TV as is common on reality TV.

I hope you can find understanding to help you overcome this.