I had no idea (ignorant on my part to assume) that so many people didn’t understand the relationship between left side bend, flat shoulder turn and lateral head movement.
First off, nothing wrong with a little lateral head movement away front he target during the backswing, especially with driver. However, you don’t want it to be excessive.
As many of you know, I’m not a big fan of flat shoulder turns and/or the lead shoulder (left for righties) getting too high at the top of the swing. I fight this issue and it’s a recipe for many things none of us are fond of. OTT, stuck arms, vertical downswing shoulder turn, etc.
Anyways, all these things are related. One would think that left side bend would be tilt toward the target, but at the top of the turned backswing, it’s tilt toward the ball.
So if you have issues with a flat shoulder turn or too much lateral movement of the upper body away from the target…or someone tells you that you are losing your spine angle at the top of the swing. You need more left side bend at the top. More easily felt as left shoulder down and out to the ball.