The reason for buttock pain after running may be too much exercise, lumbar disc herniation or hip arthritis. 1. Excessive exercise: Running requires constant contraction and pulling of muscles and tendons in the buttocks, and metabolites will be produced during the contraction and pulling process. Metabolites increase when the exercise volume is too large, and after stopping, blood circulation decreases so that the metabolites will accumulate and stimulate the buttock tissues, resulting in a painful sensation. 2. Lumbar disc herniation: running can increase the pressure of lumbar intervertebral disc and lumbar spinal canal, resulting in increased local inflammatory response, if the sciatic nerve is stimulated, the buttocks will hurt after running. 3. Hip arthritis: synovitis or osteoarthritis of the hip joint can also lead to running buttocks pain. There may be other reasons for buttock pain after running, if the improvement is not obvious or aggravated after resting, you should go to the regular hospital in time to consult the doctor, who will judge the specific cause of the disease according to the symptoms, signs and auxiliary examination, and give the correct treatment for the cause.