Rotator Cuff Strain/ Tendinopathy
The term "Rotator cuff" describes a group of four small muscles that hold your shoulder in its shallow socket while larger muscles move it.

The vast majority of injuries are the result of repetitive strains over a long period of time. One of the most common reasons that patients develop a rotator cuff tear is something called "impingement". Impingement basically means that the area where your rotator cuff tendon lives has become too crowded and the rotator cuff tendon is being pinched each time you raise your arm. Those who perform repeated overhead activities are at greatest risk for impingement and rotator cuff tendon problems. This includes athletes who play baseball, volleyball, tennis, rowing, weight lifting, swimming and archery, and jobs that include carpentry, painting, wall paper hanging, cleaning windows and washing/waxing cars. Other known risk factors for rotator cuff problems include smoking, obesity, high cholesterol and prior cortisone injection.

Scapular Dyskinesis
All of your shoulder muscles must work in a coordinated fashion to have a healthy and stable joint. Disruption of the normal rhythm of your shoulder blade creates abnormal strain on your shoulder and rotator cuff called "Scapular dyskinesis"

Scapular dyskinesis most commonly originates from weakness or imbalance of the muscles that control your shoulder blade. Sometimes the problem is caused by other shoulder conditions like prior fractures, arthritis, or instability. Irritation of the nerves that control the shoulder muscles is the culprit in about 5% of cases. .

Shoulder Impingement
Impingement is the most common shoulder disorder and accounts for about half of all shoulder complaints seen by physicians.

Those who perform repetitive overhead activity are at greater risk for impingement. This includes athletes who participate in: swimming, baseball, volleyball, weightlifting and tennis as well as jobs like: carpenters, electricians, painters and wall paper hangers.

Your successful treatment will focus on restoring your range of motion while avoiding aggravating movements i.e. reaching overhead and behind your back. If you work out at the gym, you should especially avoid overhead presses, lateral raises and push-ups. Avoid sleeping on the "bad" shoulder, especially if this causes pain. You may benefit from sleeping on your "good" side and placing a pillow between your side and "bad" arm.