The pectorals (chest) muscles are tight on most people. Since everything we do to function on a daily basis is in front of us, we tend to maintain a rounded shoulder posture. This results in tight pectoral muscles.
Unless you take time to loosen these muscles up, they continually get tight and limit our ability to reach overhead, reach back, and even just to stand in a good, upright posture.
Try out this exercise to loosen up the pectoral muscles and improve the health of the shoulder, which allows improved performance in your sports and less pain.