To maximize your full potential in the golf swing, you must have the ability to take your joints and muscles through their full range of motion. Performing exercises that focus on muscles that are chronically tight will help your become more efficient in your golf swing.
Having tight or overly developed pectorals and latissimus (chest and back) muscles can affect how your shoulders work in the golf swing. The tight and overly developed muscles tend to dominate the arm movement in the golf swing, restricting how well your shoulders can turn. Which can lead to swing compensations and even injury.