Your chest muscles are important in the golf swing to support the club at the top and help pull the arms down on the golf swing. But if they are tight or you are muscle bond, then your backswing will be restricted and you will not be able to make a full turn at the top of the swing. Furthermore, your overly tight chest muscles will tend to take over the downswing, causing the over the top move and a faulty downswing.
Stand in a shoulder width stance.
Place both hands behind your head as if in a prisoner stance and interlace fingers.
Press your elbows away from your ears to feel a stretch in your chest.
Hold position for 8 to 10 counts.