Elbow straightening pain may be caused by acute sprain, chronic strain and other reasons. 1. Acute sprain: usually the elbow joint is the flexible joint of the upper limb, the patient is easy to cause local injury after lifting heavy objects or collision, not only may have inflammatory material exudation, muscle tear, may also damage the synovial membrane, which leads to the patient to appear elbow straightening pain phenomenon. 2. Chronic strain injury: generally this is because the elbow joint, especially the extensor tendon stop, patients often due to weight lifting, excessive activities, adverse stimuli and other factors lead to the accumulation of local lactic acid, muscle stiffness and adhesion, which will not only be in the elbow straighten the pain, but also may radiate to a lot of localized parts of the pain. There are many other causes of pain when straightening the elbow, and it is recommended that patients actively seek medical attention to clarify the cause of the disease and then carry out the relevant treatment.