This exercise will improve mobility of your shoulder.
Use a tennis ball, lacrosse ball or Yoga Tune Up ball for this exercise. Place the ball on the ground between your shoulder blade and spine. Search for a trigger point and raise your arm overhead 10 times. Next, make 10 big circles clockwise and then counterclockwise. Move the ball to a new tender spot and repeat for a total of 3 trigger points. If moving the arm is too intense, simply apply pressure on the tender point and just breathe.
