Your shoulder is bothering you, so you don’t use it. If you’ve injured your shoulder or are suffering from chronic shoulder pain and you don’t use your shoulder for a long time, your joint will stiffen up.
From there, it becomes a vicious cycle. If your joint begins to stiffen up, it’s more difficult and more painful to use your shoulder. So you use your shoulder even less. Your shoulder gets more and more stiff, and eventually, the lining of the joint gets stiff. Once that happens, you won’t be able to move your shoulder much, even if you want to. It simply won’t budge past a certain point because of pain and stiffness.
In general, frozen shoulder can come on after an injury to your shoulder. Nonetheless, any condition that causes you to refrain from moving your arm and using your shoulder joint can put you at risk for developing frozen shoulder.
The shoulder slowly becomes more stiff. This is when the ligaments shorten and do not stretch, causing you to lose mobility in your shoulder. Keeping the shoulder moving, to work the stiffness out of the ligaments and tendons so adhesions can’t form, is the way to go. Because lack of use and motion is what leads to stiffness.