Frozen shoulder, also called as adhesive capsulitis, painful stiff shoulder, and periarthritis, is a condition that causes stiffness and limitations in movement of the shoulder. In frozen shoulder, the tissue around the shoulder joint becomes thick and tight, causing pain.
What Are the First Signs of Frozen Shoulder?
You may have frozen shoulder if you have symptoms such as:
- Shoulder stiffness
- Shoulder pain
- Pain may be severe
- Often worse at night
- Inability to move the arm normally
- Limited reaching (e.g., overhead, to the side, across the chest)
- Limited rotation (e.g., inability to scratch the back, put on a coat)
Frozen shoulder commonly progresses through three phases:
- Initial phase
- Diffuse, severe, and disabling shoulder pain
- Pain is worse at night
- Increasing stiffness
- Lasts for two to nine months
- Intermediate phase
- Stiffness
- Severe loss of shoulder motion
- Pain that gradually becomes less pronounced
- Lasts for 4 to 12 months
- Recovery phase
- A gradual return of range of motion that takes from 5 to 24 months
What Causes Frozen Shoulder?
Frozen shoulder (adhesive capsulitis) is often associated with other diseases or conditions, though it may not have a known cause (idiopathic).
Conditions that increase the risk of developing frozen shoulder include:
- Diabetes
- Thyroid disease, especially hypothyroidism and benign thyroid nodules
- Dyslipidemia
- Prolonged immobilization
- Stroke
- Autoimmune disease
- Parkinson disease (rare)
Frozen shoulder also often occurs after shoulder injuries, such as:
- Rotator cuff tears
- Proximal humerus fractures
- Shoulder surgery
How Is Frozen Shoulder Diagnosed?
Frozen shoulder (adhesive capsulitis) is diagnosed with a patient’s medical history and a physical examination of the shoulder joint that will include range of motion testing.
Tests that may be used to confirm the diagnosis or to rule out other conditions may include:
- Lidocaine injection test
- X-rays
- Magnetic resonance imaging (MRI)
- Ultrasound
What Is the Fastest Way to Heal a Frozen Shoulder?
Treatment for frozen shoulder (adhesive capsulitis) may include:
- Rest
- Avoiding raising the arm overhead, reaching, and lifting things
- Over-the-counter (OTC) pain medicines
- Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) or naproxen (Aleve)
- Acetaminophen (Tylenol)
- Oral corticosteroids for a short time
- Corticosteroid injections
- Physical therapy
- Surgery
- Reserved for patients who do not respond to conservative treatments
From 
https://www.uptodate.com/contents/evaluation-of-the-adult-with-shoulder-complaints?search=shoulder%20pain&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H1112788727
https://www.uptodate.com/contents/frozen-shoulder-adhesive-capsulitis?search=frozen%20shoulder&source=search_result&selectedTitle=1~35&usage_type=default&display_rank=1