Frozen shoulder is when the shoulder is painful and loses motion because of inflammation.
The joint capsule of the shoulder joint has ligaments that hold the shoulder bones to each other. When the capsule becomes inflamed, the shoulder bones are unable to move freely in the joint. Most of the time there is no cause for frozen shoulder
Cervical disk disease of the neck.
Diabetes.
Shoulder injury.
Shoulder surgery.
Open heart surgery.
Hyperthyroidism.
Decreased motion of the shoulder.
Pain.
Stiffness.
Frozen shoulder without any known cause starts with pain. This pain prevents you from moving your arm. The lack of movement leads to stiffness and then even less motion. Over time, you become unable to perform activities such as reaching over your head or behind you.