Final answer:
Pain with active but not passive movement is likely indicative of a muscle/tendon issue, such as tendinitis, which is often caused by overuse and repetitive motion.
Step-by-step explanation:
When there is pain with active movement but not with passive movement, it often indicates a muscle/tendon issue rather than a joint/ligament issue. The pain experienced during active movement can be related to conditions such as tendinitis. Tendinitis is the inflammation of a tendon, which is the fibrous connective tissue that attaches muscle to bone. This condition is frequently a result of repetitive motions that strain the tendons over time, leading to inflammatory response and pain during movements that engage the affected muscle and its tendon. However, in passive movement, the muscle does not contract, and therefore, movement does not evoke the same pain.
People who perform the same movements repeatedly in their jobs or sports activities, such as tennis, golf, or swimming, are at a higher risk for developing tendinitis. Tendinitis can lead to severe cases where the tendon may tear, and repairing this may require surgery. Since tendons have a low blood supply, the healing process for tendon injuries is slow, making prevention and early treatment crucial for those at risk.