Pain in the humerus, your upper arm bone, can come from the bone itself, the 13 muscles attached to it, the nerves running along it, or even organs elsewhere in your body sending pain signals to your arm. Pinpointing the cause depends on where the pain is, how it started, and what other symptoms you notice.
Muscle and Tendon Problems
The humerus is connected to 13 muscles, which means a lot of soft tissue can become irritated, strained, or inflamed around it. The most common culprits are rotator cuff injuries, tendinitis, and bursitis.
Rotator cuff problems affect the group of muscles and tendons that stabilize your shoulder joint. Pain from these injuries typically sits near the top of the humerus and worsens when you lift your arm overhead or reach behind your back. You don’t need a dramatic injury to develop rotator cuff pain. Repetitive motions, sleeping on one side, or gradual wear over time can all do it.
Tendinitis, inflammation of a tendon, commonly develops where the biceps tendon attaches near the top of the humerus. Tennis elbow (lateral epicondylitis) affects the outside of the lower humerus near the elbow. Both tend to produce a dull ache that sharpens with specific movements, like gripping or twisting. Bursitis, where the fluid-filled cushions around the joint become inflamed, creates similar pain patterns near the shoulder. Shoulder impingement syndrome, where tendons get pinched during arm movement, is another frequent source of pain that radiates into the upper arm.
Fractures and Bone Injuries
A broken humerus is hard to miss in most cases, but not all fractures are obvious. Stress fractures or hairline cracks can produce a deep, persistent ache without the dramatic swelling of a full break. Symptoms of a humerus fracture include pain, swelling, tenderness, bruising, inability to move your arm normally, and sometimes a visible bump or deformity.
The humerus can break in three general areas, and each feels different. A break near the shoulder (proximal fracture) causes pain high in the arm and limits your ability to raise it. A mid-shaft fracture produces pain in the middle of the upper arm and often damages the radial nerve, which runs along the back of the bone. A break near the elbow (distal fracture) causes pain, swelling, and stiffness at the elbow joint.
Recovery times vary widely. Nonoperative treatment for a proximal fracture typically starts with a sling and no shoulder movement for the first two weeks, while a shaft fracture may require a special brace (called a Sarmiento brace) for several weeks. Full healing can take several weeks to several months depending on severity and location. Surgical cases often begin physical therapy sooner, sometimes immediately after the procedure.
Nerve-Related Pain
Because your humerus is connected to so many muscles and nerves, an injury to one often affects the others. The radial nerve is especially vulnerable. It runs down the back of your arm from your armpit to your hand, controlling movement in your elbow, wrist, and fingers. When this nerve is compressed or damaged, you may feel numbness, tingling, or a burning sensation along the back of your hand and your thumb, index, and middle fingers.
More severe radial nerve damage can cause difficulty straightening your arm at the elbow, weakness in your fingers, or trouble bending your wrist back, a condition sometimes called “wrist drop.” This nerve damage frequently accompanies humerus fractures but can also result from prolonged pressure on the arm, like falling asleep with your arm draped over a chair.
The brachial plexus, a network of nerves that runs from your neck through your shoulder and down your arm, can also cause humerus-area pain when injured or compressed. Thoracic outlet syndrome, where nerves are pinched between your collarbone and first rib, sometimes sends pain down into the upper arm as well.
Arthritis and Joint Conditions
Osteoarthritis wears down the cartilage at the ends of the humerus where it meets the shoulder or elbow joint. The result is a stiff, achy pain that worsens with activity and improves with rest, often accompanied by a grinding sensation during movement. This is more common after age 50 or in people with a history of joint injuries.
Rheumatoid arthritis can affect the same joints but tends to cause pain on both sides of the body, along with morning stiffness that lasts more than 30 minutes. Swelling, warmth, and fatigue are common alongside the joint pain.
Referred Pain From Other Organs
Sometimes humerus pain has nothing to do with the arm at all. Your body can send pain signals from internal organs to your arm through shared nerve pathways, a phenomenon called referred pain.
The most important example is a heart attack, which can cause pain in your left arm, shoulder, jaw, or teeth without any arm injury. If your arm pain comes with chest tightness, difficulty breathing, dizziness, or nausea, treat it as a medical emergency.
Other organs can refer pain to the arm or shoulder area too. Gallstones and pancreatitis sometimes cause upper back and shoulder pain. Lung problems and liver conditions can also produce referred shoulder pain. The key distinction is that referred pain shows up without any obvious injury, doesn’t change much with arm movement, and usually comes with other symptoms like digestive trouble or shortness of breath.
Less Common Causes
Shingles, a reactivation of the chickenpox virus, can cause burning or shooting pain along a strip of skin on the arm before a rash appears. Fibromyalgia produces widespread pain that can include the upper arms, typically alongside fatigue and tenderness at multiple points across the body. Cellulitis, a bacterial skin infection, causes redness, warmth, and swelling that spreads, along with pain in the affected area. Deep vein thrombosis, a blood clot in a deep vein, can occasionally develop in the arm and causes swelling, warmth, and a heavy aching sensation.
Narrowing Down the Cause
A few patterns can help you sort out what’s going on. Pain that started after a fall, collision, or sudden twist points toward a fracture, strain, or tendon tear. Pain that built up gradually over weeks, especially with repetitive arm use, suggests tendinitis, bursitis, or impingement. Pain accompanied by tingling, numbness, or weakness in the hand likely involves a nerve. Pain that appeared without any arm injury, particularly with chest or abdominal symptoms, may be referred from an organ.
Location matters too. Pain near the shoulder points toward rotator cuff problems, proximal fractures, or impingement. Mid-arm pain suggests a shaft fracture, muscle strain, or radial nerve issue. Pain near the elbow is more consistent with tennis elbow, a distal fracture, or arthritis. Deep bone pain that doesn’t ease with rest or worsens at night warrants prompt evaluation, as it can occasionally signal a bone infection or tumor.