When Muscle Pain Signals More Than a Workout: The Link Between Muscle Aches and Internal Organ Problems

Muscle pain is often dismissed as a byproduct of physical exertion, poor posture, or minor injuries. While these are common and usually harmless causes, not all muscle pain originates in the muscles themselves. In some cases, it may be a red flag pointing to deeper, internal health problems—specifically issues related to internal organs.

Understanding Referred Pain

The human body is a complex network of nerves that can sometimes blur the lines between the source of pain and where it is felt. This phenomenon, known as referred pain, occurs when pain from an internal organ is perceived in the musculoskeletal system, often in the back, shoulders, or abdomen. Because our brains are more familiar with receiving pain signals from muscles than from internal organs, it can misinterpret the source.

Common Internal Organ Issues That Cause Muscle-Like Pain

1. Heart Problems

Cardiac issues, especially those involving reduced blood flow to the heart muscle (like angina or a heart attack), can cause pain that radiates to the shoulders, arms, neck, or upper back. This can easily be mistaken for muscle strain or tension.

2. Kidney Disorders

Kidney stones or infections may manifest as a deep, dull ache in the lower back or flanks, sometimes resembling muscle soreness. However, this pain is often persistent and doesn't improve with rest or movement—unlike typical muscle pain.

3. Liver or Gallbladder Disease

Conditions such as hepatitis, gallstones, or liver congestion can cause pain in the right shoulder or upper back. This occurs because the liver and gallbladder share neural pathways with the shoulder area through the phrenic nerve.

4. Pancreatitis

Inflammation of the pancreas can lead to pain that radiates to the back, especially the upper back, and can mimic muscular pain. Unlike a pulled muscle, though, the pain from pancreatitis often worsens after eating and is associated with digestive symptoms.

5. Lung Problems

Pleurisy (inflammation of the lung lining), pneumonia, or a pulmonary embolism can cause pain in the chest, shoulders, or upper back. This pain can feel muscular, but it often intensifies with breathing or coughing.

6. Gastrointestinal Issues

Problems like acid reflux or a perforated ulcer can cause upper abdominal pain that radiates to the back. In severe cases, the discomfort may feel like a strain in the lower or mid-back muscles.

When to See a Doctor

It's important to recognize when muscle pain might be more than just physical fatigue or overuse. Here are a few red flags:

The pain is severe, sudden, or persistent.

It's not relieved by rest, massage, or over-the-counter painkillers.

It's accompanied by other symptoms like fever, shortness of breath, nausea, dizziness, or changes in urine or stool.

It worsens after eating or with certain positions.

There's no obvious cause, like recent physical activity.

While most muscle pain is harmless and related to physical strain, it's wise not to ignore persistent or unexplained aches—especially if they come with other symptoms. Understanding the possibility of referred pain from internal organs can help individuals and healthcare providers identify more serious health concerns early on.