What is Shoulder Pain?
The shoulder joint is surrounded by a capsule known as the joint sheath. If this capsule develops adhesions, a condition called frozen shoulder may occur.

On this capsule are ligaments that connect the joint. Excessive strain or looseness in these ligaments can cause partial or complete dislocation of the shoulder joint.
On top of these ligaments lie muscle tendons, which are responsible for the movement of the shoulder. There are four major rotator cuff tendons in the shoulder. Tears in these tendons can also lead to pain.
Within the shoulder, there is a bursa called the subacromial bursa, one of the largest sacs in the body, which facilitates smooth joint movement. This bursa can become inflamed due to rheumatic conditions.
Covering all these structures is the deltoid muscle, one of the strongest muscles that gives the shoulder its shape.
Damage, strain, tearing, or trauma in one or more of these structures can lead to shoulder pain along with other complaints.
The area where the humerus (upper arm bone), scapula (shoulder blade), and clavicle (collarbone) meet forms the shoulder joint. The shoulder is a highly mobile joint that can move in four directions.
Although shoulder pain typically originates from the shoulder joint, it can also be referred from other regions—most commonly from a cervical disc herniation in the neck.
Shoulder pain may occur due to abnormalities in any of the above-mentioned components.

What Are the Causes of Shoulder Pain?
The most common causes of shoulder pain stem from its own anatomical structure. These include:

• Impingement of the shoulder tendons
• Frozen shoulder
• Calcific tendinitis due to calcium buildup in the tendons
• Shoulder instability or subluxation
• Myofascial pain caused by strain in the surrounding muscles
• Post-stroke shoulder pain

Less frequently, external causes can be responsible, such as:

• Inflammatory rheumatic diseases
• Upper lung cancers
• Liver, gallbladder, or spleen problems
• Cervical disc herniation

Other causes include:

• Trauma or direct impact to the shoulder
• Clavicle fractures
• Bursitis, fibrositis, myositis, tendinitis
• Shoulder dislocations or fractures
• Sleeping continuously in improper positions
• Spinal injuries
• Heavy lifting, window cleaning, or similar activities
• Shoulder impingement syndrome
• Cardiovascular diseases, chronic lung disease, diabetes, and neck disorders
• Stroke (hemiplegia)

What Are the Symptoms That Accompany Shoulder Pain?
In addition to pain, symptoms may include tenderness, increased warmth, redness, limited range of motion, the “epaulet sign” seen in dislocations, stiffness, or presence of a mass in the shoulder.

How is Shoulder Pain Diagnosed?
Diagnosis is generally made through the patient’s medical history and a thorough physical examination. Most shoulder pain is due to soft tissue issues. Since degenerative changes usually appear later in life, standard X-rays may not show the problem. CT scans are rarely needed. MRI is the best imaging technique to assess both bones and soft tissues. In suspected nerve injury, EMG (electromyography) may be required.

How is Shoulder Pain Treated?
Shoulder pain caused by muscle strain or incorrect movements often resolves on its own in a short time. However, trauma-related injuries may require emergency treatment.
The causes of shoulder pain vary widely, from tumors to trauma. Therefore, if pain is accompanied by fever, occurs at night, causes weight loss, doesn’t change with arm movement, and doesn’t respond to painkillers, tumors or infections must be ruled out first. Once other causes are excluded, the treatment should focus on the specific diagnosis. Most shoulder conditions benefit from physical therapy.
For acute pain, ice therapy is highly effective. The shoulder should be rested as much as possible, used minimally, and anti-inflammatory medications should be taken. Ice should be applied 3–5 times a day for 15 minutes each session.
For patients with severe pain or those with traumatic injuries, a shoulder sling may be used, though sling use should be limited to a short duration.
In chronic pain cases, a different treatment approach is needed. Physical therapy becomes more important. Exercises to improve joint range of motion and muscle strength, along with shockwave therapy (ESWT), may be beneficial.