Pectoralis stretching (Pectoralis stretch, middle fibers, arm bent, standing; 01)

Stand up straight in a doorway.
Place your affected arm at shoulder height on the door frame.
Bend your elbow to 90 degrees so that your forearm runs up the door frame.
Place one foot in front and one behind for stability.
Keep your spine straight and rotate your body away from the door frame, while gently pushing forwards.
You should feel a stretch across the front of your chest.