Shoulder cars are a great mobility exercise for increasing the range of motion in your shoulders!
Start with your hand at your side
Your palm should be flat on your side
Rotate your arm forward and upward as high as you are able to go without twisting your torso
Once you get to the top of the movement, rotate your palm out 180 degrees and continue rotating your entire arm through the circular path
Tip: Use a wall to ensure the rotation of your arm and hand stays within the same plane throughout the entire movement