It is very easy on your short game pitches and chips to start rocking your shoulders as opposed to rotating them. Because these are shorter swings where the club head never ends up behind the golfer, it is easy to forget to rotate the shoulders and simply to take the club back by swinging the arms, lifting the right shoulder and dropping the left. You will know if you are lifting as opposed to rotating your shoulder if the point of your right shoulder gets closer to your right ear. This will happen if you lift your shoulder. If you rotate, your shoulder will remain the same distance from your ear.
Lifting the shoulder causes several problems, most important of which is thin or fat contact. This is because the fixed geometry of rotating your shoulders around your upper spine is destroyed.
As an exercise place the point of your folded right elbow very close your stomach just above your right hip bone. Keeping it there hit some balls by bringing the club back to horizontal and hitting through the ball with shoulder and hip rotation only. This shortened swing will be performed mostly with your wrists.
Your right elbow should come away from your stomach as you make contact with the ball. Your hips will have to drive forward towards the target. Make sure you follow through till the club is at least horizontal on the follow through. Stay relaxed and make the move as fluidly as possible. No need to restrict this routine to your short game. Even on a full swing prolonged right elbow intimacy with the body is beneficial. Keep your eyes on a point on the back of the ball where you want to make contact.
You should instantly feel the difference and be getting crisp contact. Make sure the angle between your lower and upper legs remains constant. Keep your spine angle constant also. Get your short game back on track.