Pain in the left arm and shoulder can be symptoms of a life-threatening condition or a simple injury. Any type of acute, intense pain should be treated by a medical professional immediately.
One of those life-threatening conditions could be a heart attack. When a blocked artery cuts off blood supply to the heart it can cause acute pain in the chest, back, shoulder, neck and arm. The pain can be mild to severe and feel like pressure, tightness, heaviness or burning.
Meningitis causes pain in the neck and shoulders but is usually accompanied by fever, flu-like symptoms and a stiff neck. The condition typically comes on suddenly and progresses quickly.
A herniated disc in the cervical spine causes acute pain when pinching a nerve, which can cause pain in the neck and shoulder and be accompanied by numbness or tingling in an arm.
Wear and ageing cause changes in the joints of the neck (facet joints) or at the margins of the discs, called spinal stenosis. This is a chronic pain that usually progresses gradually.
Symptomatic cervical disc degeneration
Symptomatic cervical disc degeneration usually causes low level chronic pain that can radiate to the shoulder and down the arm. This ageing-related condition's pain may flare up from activity.
Pulling a muscle in your shoulder or neck area will cause pain in the muscle area, which may also radiate down your arm and be accompanied by a stiff neck.