Trying to connect the rapid head movement to the alcohol issues will be very difficult. No doctor will take you seriously. They will just tell you to stop drinking or some such advice. Top of the head sounds strange.

You could spend thousands of dollars trying to resolve this and still have no answers, as you have after the MRI and CT.

Pushing for answers puts you at risk of being labeled a hypochondriac or cyberchondriac. The later is the former but with information from internet browsing.