Swelling and pain on the back of the foot may be caused by physiological reasons such as excessive exercise and inappropriate shoe size, or it may be caused by pathological factors such as trauma and autoimmune diseases. 1. Physiological reasons: there are a lot of soft tissue structures attached to the dorsum of the foot, if walking for a long period of time or when the amount of exercise is relatively large, it may cause fatigue injury to the soft tissue of the dorsum of the foot, resulting in congestion and edema of the soft tissues, which causes the symptoms of dorsal swelling and pain; in addition, if the size of the shoes is not suitable, which will cause the dorsum of the foot and the shoes to repeatedly impact or friction, the above symptoms may also occur. 2. Pathological factors: trauma to the dorsum of the foot may also cause congestion and edema of the soft tissues or abnormalities of the physiological structure leading to symptoms of swelling and pain, such as avulsion of the bones of the dorsum of the foot, subluxation, smashing, etc.; patients with autoimmune diseases may also experience accumulation of the dorsum of the foot, resulting in the symptoms mentioned above, such as rheumatoid arthritis and gout. There may be other reasons for the swelling and pain on the back of the foot, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.