The shoulder is a ball-and-socket joint that can move freely in all four directions. However, this mobility comes at the expense of its stability. It can be easily dislocated and painfully pulled out of its correct position.

Several muscles and ligaments hold the shoulder joint in place. These must be loose and elastic for the joint to move freely and fluidly. This also means that they are more prone to tears and injuries.

In India, 30 per cent of adults between 30 and 70 years have shoulder pain. This problem may occur due to a traumatic injury or accident or seemingly for no reason at all. It can happen to anyone.

The most typical cause is joint wear and tear, often due to repeated use. Any repetitive movements, such as cooking, painting or washing clothes, can cause this. Pain may be accompanied by strange sounds in the joint.

Shoulder pain occurs in 30 per cent of people with diabetes. It is usually only on one side. It lasts a month or so and disappears but may be followed by pain on the other side. It is known as “frozen shoulder” and the medical name “adhesive capsulitis”. It occurs when high blood sugars cause glycosylation of the collagen in the shoulder capsule, making it sticky. It restricts activity. Affected persons cannot raise their arms over their heads, put on clothes or, sometimes, even comb their hair. Both shoulders are seldom affected simultaneously.

People today lead a less active life than before, either because of studies, work pressure or computer use. Often, they slouch in front of the computer or work on laptops sitting on the bed or sofa. Sitting with the head and neck tilted at an angle can cause shoulder pain. Remember, the adult head weighs eight kilogrammes and has to be supported entirely by the small neck bones.

Many people do not go out in the sun at all. Even when they do, they are fully clothed. The sunshine vitamin (D3) is formed when the sun’s rays hit the skin. If you do not go out into the sun at all, or you are fully clothed when you do so, you are likely to become deficient in Vitamin D3. Between 70 and 80 per cent of Indian adults are deficient in Vitamin D3. The neck bones become weak easily as they are small. Then, they are unable to support the eight-kg head. The bones get squashed, move away from their normal position and impinge on the nerves running to the shoulder and arm, resulting in shoulder pain.

Sometimes, rheumatoid arthritis or osteoarthritis, affecting many joints in the body, may also affect the shoulder joint. The pain is likely to be symmetrical, affecting both joints. There may also be redness and swelling.

Organs in the abdomen, like the liver and gall bladder, can irritate the underside of the diaphragm. It can then manifest as pain in the shoulder.

Pain in the left shoulder may also occur as a result of a heart attack. It can radiate to the jaw, the back or down the left arm. Breathing may become difficult. This is more likely to happen if you have other risk factors such as diabetes, hypertension or elevated lipids.

Shoulder pain is evaluated with X-rays, CT scans and MRIs. Blood tests may have to be done to rule out infections, arthritis and diabetes. Fractures, dislocations and heart attacks need specialised treatment.

Rest, ice, heat and painkillers will reduce discomfort and swelling. Physiotherapy, passive movements and active exercises will help to restore mobility and function.