Targeting your pectoral muscles is important if you are a desk worker or sit a lot generally as they will tend to shorten and become tight. We have two pec muscles that attach from the sternum and front ribs to the top of the arm or humerus.
To stretch the pectoral muscles, stand by the side of a wall or doorway and have your arm positioned at about 90 degrees. Then take a small step and lean forward. Hold that pressure and turn to the opposite side until you feel the stretch across your front chest.
To stretch in lying, first lie on your side with your top leg bent and bottom leg straight. Lift your arm up to the sky and then twist backwards and allow your arm to come close to the floor. Keep your elbow bent in this position and hold the stretch for 30 seconds.