Originally Posted by Ernest Jones
Saevel's bang on here. You may have a different fault that's the priority which may, in turn, fix the head movement as a byproduct.
I guess I could do a little work for the guy. Its a Friday, its bleeping cold. @Ernest Jones's Polar Vortex from Canada is kicking my ass, and I got nothing better to do then take a shot in the dark on this one.
So to @Bwood6017
Check out this thread, Look for drills for key 1 (steady head). There are some good introductory information there as well as drills.
Just because I think the OP might be suffering from bad posture. Lower the head a bit, and hunch the upper back, don't arch the lower back. Usually up an down head movement is caused by poor posture, but it could be caused by a poor backswing as well. So, that is why I say post a video of the golf swing.