Group of muscles and tendons in the shoulder are called rotator cuff. Rotator cuff disorder happens in cases of damage or irritation of tissues in the shoulder. The main symptoms of rotation cuff injury is pain when you try to raise you arm, preventing you to do even simple tasks, and it can be worse at night.
There are several reasons why rotator cuff disorder appears, one of them can be soreness of some tendons, and witch is cord that attaches muscles with bones. Main jolt in shoulder is connected between arm bone and shoulder blade, allowing for very wide range of movements and motions. The rotator cuff is surrounded by several muscles that keeps shoulder jolt steady and in place.
There are several symptoms that rotator cuff disorder can manifest, among them; soreness or inflammation of the bursa sac (which is a sac of fluid that acts as a cushion between tendons and the bones in the shoulder), inflammation or soreness of some tendons, witch are cord that attaches muscles with bones, complete or partial tears of tendons of rotator cuff, or calcium build up in the tendons, etc.
Any overuse of your shoulder, whether it may be exercise, physical activities, or simply playing some sort of sport or recreation to hard, can be the cause of rotation cuff injury, or pain in the shoulder or bursa sac.
Also normal wear of the tendons and muscles in your shoulder that builds up for years of use, may also be one of the causes. Over the years, excessive use of your shoulder may fry or thin tendons in rotator cuff, also cutting the blood supply to the shoulder, as well.
Both of these causes may lead to the same outcome; process called impingement (case when bone rubs against tendon in your shoulder), and this process inflames and damages the tendons.
In order for your doctor to diagnose rotator cuff injury, you will first feel pain in the shoulder, and maybe weakness or stiffness of the shoulder movements. Doctors may also ask you about your medical history of shoulder injuries, physically examine you, and maybe does the X ray check. If your problem is still unclear, he may also test your shoulder with ultrasound or MRI, in order to get a clearer picture of your injury.
Treatment of rotation cuff injuries is very important. This injury, if untreated, may prevent you of normally doing simplest everyday tasks, like combing your hair, or buttoning your shirt, and ultimately, you may not be able to use normally or lift your arm, altogether.
After the examination, your doctor may prescribe you with pain medications, physical therapy, and set of exercises for you to do after therapy is over, in order to prevent your injury to repeat, etc.
Thing for you to do yourself, in order to help your injury is to avoid activities and positions that are uncomfortable, rest your shoulder a lot, apply ice packs if pain get too strong, and take some anti inflammatory drugs, like NSAIDs, ibuprofen, etc.