After running the side of the foot pain, to consider the sports intensity, unreasonable sports, primary diseases, fatigue fracture and so on. 1. Higher intensity of exercise: most of them are related to the high intensity of exercise and the greater force on the feet, especially for obese patients, after high-intensity exercise, the feet will bear more stress, and there will be pain and discomfort in the feet, which will generally improve after rest. 2. Unreasonable sports: such as incorrect posture, or wearing hard shoes during sports, can also cause such a situation, so develop a scientific sports, running, pay attention to wear sports shoes, can also effectively avoid foot pain. 3. Primary diseases: plantar fasciitis and flat feet can cause pain on one side of the foot, the whole sole of the foot, or the heel. 4. Fatigue fracture: prolonged high-intensity exercise, but also need to rule out the possibility of fatigue fracture, especially military personnel and athletes. This can be clarified by X-ray examination. If you have persistent pain on one side of your foot after running, we suggest you to consult the hospital in time and improve the relevant examination.