In general, referred pain to the shoulder is a result of irritation to the diaphragm. A typical example of such irritation is inflammation of the liver or gallbladder. This unique way of presentation is due to the common innervation of the skin around the shoulder and the diaphragm. This common pathway for pain signal confuses our brain which indicates to us the problem coming from the shoulder when it actually originates from the abdomen.
At times, pain around the chest and shoulder may also come from significant gastric reflux. This discomfort can be difficult to pinpoint and may be perceived over a large area around the upper body including the chest, neck and shoulder.
Shoulder pain not related to the digestive tract may come from the cervical spine. Such pain may also couple with numbness over the shoulder and the upper limb. At times, one may also experience weakness due to significant nerve compression.
