What Causes Feeling Of Bubbles Moving Under Scalp After An Accident?

I was in a minor car accident the other day and bumped my head fairly hard on the side window. X-ray of my neck showed no problems, it was assumed I had sustained a minor concussion. The past couple of days it feels like there are little bubbles moving under my scalp although I have no bumps or lesions of any kind. Related at all? Just coincidental or am I just hyper sensitive to anything going on right now?