Frozen shoulder

Frozen shoulder typically develops in three stages, each lasting several months: 

• Freezing stage: Pain occurs with any shoulder movement and your range of motion gradually decreases. Pain at night is common and can disrupt sleep.
• Frozen stage: Pain may decrease, but stiffness increases. Your shoulder may feel locked, making daily tasks challenging.
• Thawing stage: Shoulder movement slowly returns, though full mobility can take time to regain. 

You may notice difficulty reaching overhead, behind your back or performing simple tasks like combing your hair. Symptoms often build slowly, so early signs can be easy to dismiss, but recognizing them sooner can lead to more effective treatment.

The exact cause of frozen shoulder isn't fully understood. Over time, the connective tissue capsule surrounding your shoulder joint thickens and tightens, restricting movement. This process develops slowly, which is part of why the condition can be easy to overlook in its early stages. 

Certain factors can increase your risk of developing frozen shoulder, though having one or more of these does not mean you'll experience the condition: 

• Diabetes
• Extended periods of immobilization following a fracture, injury or shoulder surgery
• Being a woman
• Being over the age of 40 

Diagnosing frozen shoulder usually begins with a physical exam. Your doctor will evaluate how far you can move your shoulder both actively, on your own, and passively, when assisted by the doctor. Sometimes an anesthetic injection may be used to help assess your range of motion without pain. 

In some cases, imaging such as X-rays or an MRI may be ordered to rule out other conditions, such as rotator cuff injuries or arthritis, and confirm an accurate diagnosis.