The possibility of shoulder pain originating from the heart is a serious concern that warrants careful consideration. While most instances of discomfort in the shoulders stem from muscle strain, injury, or joint issues, cardiac events can sometimes present in seemingly unrelated body areas. The heart is typically associated with chest pain, but the body’s complex wiring means that pain signals can manifest in locations like the jaw, back, or shoulders. Understanding the difference between musculoskeletal and heart-related pain can be life-saving.
The Mechanism of Cardiac Referred Pain
Referred pain is the phenomenon that allows heart pain to be felt in a distant location like the shoulder. This occurs because the sensory nerves carrying signals from the heart share pathways with nerves serving the upper body, including the shoulders and arms, as they enter the spinal cord. Specifically, visceral pain fibers from the heart join somatic sensory nerves from the shoulder at the T1 to T4/T5 spinal segments.
When the heart muscle experiences pain, such as during a heart attack where blood flow is restricted, the brain receives a jumbled signal. Because the brain is more accustomed to receiving signals from the somatic nerves of the shoulder, it mistakenly interprets the visceral pain signal as originating from that region. While referred pain from the heart is most commonly felt on the left side, the neural pathways allow the pain to be perceived on the right side or bilaterally, though this presentation is less typical.
Distinguishing Cardiac Pain from Musculoskeletal Pain
Evaluating the quality and context of the pain helps distinguish between cardiac and musculoskeletal issues. Cardiac pain is usually described as a diffuse, heavy, crushing, or squeezing sensation, rather than a sharp or localized ache. This discomfort tends to be persistent and does not improve with changes in position, rest, or gentle movement. The pain may also intensify with physical exertion or emotional stress, which are common triggers for heart-related symptoms.
A strong indicator of cardiac involvement is the presence of accompanying systemic symptoms. These can include profuse sweating, nausea, unexplained dizziness, or shortness of breath. The pain may also radiate from the shoulder to the neck, jaw, or back, creating a pattern highly suspicious for a heart issue. In women, older adults, or those with diabetes, a heart attack may present with atypical symptoms where shoulder pain is the primary or only complaint.
In contrast, musculoskeletal pain typically has a more localized and reproducible nature. This pain is often described as sharp, aching, or tender to the touch, and it can be precisely pinpointed to a specific spot in the joint or muscle. Musculoskeletal pain is usually provoked or worsened by specific movements of the arm or shoulder, and it may be relieved by rest or finding a comfortable position. If the pain is reproducible by pressing on the shoulder joint or muscle, it is far more likely to be a non-cardiac issue.
Common Non-Cardiac Causes of Bilateral Shoulder Pain
While a cardiac cause must always be considered, pain in both shoulders is most frequently a result of common orthopedic or systemic conditions.
Orthopedic and Systemic Causes
- Poor posture or sustained overuse, such as from repetitive work or prolonged computer use, strains the tendons and muscles connecting the neck and shoulder girdle. This causes a generalized, achy tension that worsens throughout the day.
- Systemic inflammatory conditions like Rheumatoid arthritis, an autoimmune disease, cause symmetric pain, swelling, and stiffness in the shoulder joints.
- Polymyalgia rheumatica causes stiffness and aching, typically in the shoulders and hips, which is often worse in the morning.
- Referred pain from non-cardiac organs, such as the gallbladder or pancreas, can occasionally cause discomfort in the right shoulder or, less commonly, bilaterally.
- Cervical radiculopathy, a pinched nerve originating in the neck, causes pain that travels down into one or both shoulders, often accompanied by numbness or tingling. Unlike a cardiac event, this nerve pain is often positional and may be aggravated by turning or tilting the head.
- Tendonitis and bursitis, which involve inflammation of the tendons or fluid-filled sacs around the joint, can occur in both shoulders, especially with repetitive overhead motions.
When Shoulder Pain Becomes a Medical Emergency
Any shoulder pain that occurs suddenly and without a clear cause, such as an injury or strenuous activity, should be treated with extreme caution. Symptoms requiring immediate attention include the sudden onset of severe pressure or tightness in the shoulder, especially if it does not subside quickly with rest.
Immediate help is necessary if the shoulder pain is combined with shortness of breath, a cold sweat, lightheadedness, or nausea. Pain that radiates up to the jaw or neck, or across the chest, is a concerning red flag. If these signs are present, contact local emergency services immediately rather than attempting to drive to a hospital.