It’s nothing you haven’t heard before, thoracic rotation is key to an efficient golf swing. Good separation between the upper body and lower body is critical for developing speed and maintaining a good posture during the golf swing. Limited thoraco-lumbar mobility causes compensation patterns in the swing. In the backswing, you’ll see golfers stand up straight and lose the integrity of their postural angles, some will get really flat with their shoulder plane, some will extend and tilt their spine towards the target. Whatever the tendency may be, in order to get the feeling of the club getting up and around the body in the backswing, golfers with a lack of thoracic rotation will place excessive rotational stress on the lumbar spine or misuse/overuse their shoulders to compensate. Play enough golf with this underlying issue and you can bet the onset of these pains/injuries are knocking on the door.