Atlas, Your girl friend is 100% correct. This was an anxiety and OCD response to that movement. I guaranty that if you let this continue, you risk losing her. I've seen it happen before. She does not want to be your nursemaid.

If you respond like that to a moment of an excited hug or other movement during an expression of emotion or intimacy, it will be like driving a knife into her heart.

Go to a bowling center and pick up a bowling ball from the rack. Drop is on the floor from 30 cm or so. Then, drop it on your foot from the same. I dare you. OUCH. Smashed toes.

Look up flash backs. This is similar to a flashback. They can be triggered by benign events that relate to a real event.

This of how you respond when you observe something. Think of how you react when you see a guy hit in the groin. Your abdominal muscles tighten and you feel an electrical zing in your body. BUT, you were never touched.

I get the same response when I see somebody hit in the head on TV. But, I recognize the why I sense those feelings and move on.

You need to learn how to recognize these movements and your reaction and move on.

btw, Why did you go to the doctor?
What did you expect the doctor to do for you?

That doctor could not diagnose whether you had or didn't have a simple concussion. In your anxiety state, it would be like trying to tell is a child who just climbed out of the pool dripping wet peed in the pool 5 minutes earlier. The wet condition hides any evidence.

You anxiety hides any evidence of a simple concussion.