… Continued …
The affected shoulder tends become passive in daily activities. The stiffness in the stage two (adhesive stage) of the disease can make the shoulder movement get worse (see also stages of how frozen shoulder progresses in this post).
Weakened muscles are commonly caused by lack of physical activity that involves the muscles surrounding the shoulder.
Even you may say ‘not at all’ when it comes to any exercise or movement that uses the affected shoulder. On the other hand, it’s important to remain active as much as you could (especially with the affected shoulder joint) to boost the recovery.
Other possible reasons may include:
The inflammation in the stage one of the disease may cause muscle spasm
Stage one is a painful phase. It is often referred to as freezing stage, the time of when the affected shoulder will begin to ache and become painful with movement. Typically, increasing pain occurs in the evening or nighttime (see more in here)!
The tight and thickened capsule of connective tissue in the shoulder may lead to muscle spasm, too. Furthermore, some patients may experience generalized ache that is not easy to pinpoint.
Poor sleep may have an effect, too
In fact, the pain of the problem can disturb the quality of your sleep. When your joint is painful, you may difficult to fall asleep.
Unluckily, pain and sleep deprivation can lead to a vicious cycle. While the pain can cause sleep deprivation, lack of sleep itself can make the pain become painful even more.
And this vicious cycle may affect the muscles, too – especially for muscle surrounding the joint. According to one study, sleep deprivation may have contribution to increase the risk of developing muscle pain.