When you move your arm, your scapula (shoulder blade) has to move as well. What we typically see in patients with shoulder pain is that the muscles between the spine and scapula (shown in the video) are tight and restrict the scapula from properly moving. Once you lift your arm past 90 degrees, your scapula has to rotate upwards. If the muscles around the scapula are restricting movement, when you go to lift your arm, the humerus (upper arm bone) will jam into the AC joint (top of the shoulder) and can cause pain. By doing these two exercises, you’ll relieve some of the tension in muscles between the spine and scapula, and regain awareness of how to allow your shoulder blade to move.