The common causes of pain in the inner side of the elbow back bend are injury, swelling compression, cervical spondylosis, rheumatism, gout and so on. 1. Injury: acute and chronic injuries to the elbow joint cause inflammatory reactions and localized pain. The elbow joint is prone to injury because of its combination of weight-bearing and fine activities. Commonly, epicondylitis of the humerus will cause pain on the inside of the elbow. 2. Swelling compression: when the elbow joint bone or soft tissue in the swelling, due to the swelling of the compression will also lead to pain. Such as nerve sheath tumor. 3. Cervical spondylosis: compression caused by cervical spondylosis results in nerve root compression in the upper limb, resulting in elbow pain. 4. Rheumatism: Rheumatoid arthritis can cause redness, swelling, heat and pain in the elbow joint. 5. Gout: Gouty arthritis can also cause pain in the elbow joint. In serious cases, it is recommended to actively seek medical attention to clarify the cause of the disease and carry out targeted treatment.