To stretch and relax the pectoralis and deltoid muscles the muscles of the arms, as well as the ligaments, capsule and tendons attached to the shoulder.
Stand with legs slightly apart. Place both hands behind your back and lock your fingers together.
Gradually push your hands downwards and slightly upwards. Stick your chest out and take a very deep breath. Hold this for a few seconds, relax and repeat.
During the stretch be sure to keep your back as upright as possible,