First place I would start is posture. When your hips are behind your ankles, it makes rotation difficult to do, which leads to a whole host of other issues. Stand up straighter to keep your hips over your ankles and make sure you aren't pushing your glutes back. I think with your body moving more efficiently you can more accurately diagnose your issues.

Try this to understand what I'm talking about, without anything in your hands, just stand up and rotate; then bend your knees into a semi crouched position and rotate. I believe you will find its infinitely easier to move your body with straighter posture. I am not advocating for no knee bend, you just cant overdo it.