question: My son is 5 years old and for a year I ve noticed for the first time usually when he s watching tv or laying in bed still that he moves his right shoulder blade by swinging his elbow towards back and it makes a loud grinding and popping noise. Since 3 months ago it has started to actually hurt and his family Dr noticed slight asymmetrical shoulder blade on the right side. Well now he s starting to complain and its still on the right but is saying the left is starting to hurt and will swing his arms back and forth fast for a 15 second period and stop for about 3 minutes and do it again till he falls asleep or does something active to take his mind off of it. Has anyone! heard of this? If so, what causes it usually?