Walking a lot of left foot surface swelling and pain, may be caused by overwork, but also can not be ruled out due to synovitis, fasciitis and other factors, the specific circumstances need to be judged under the guidance of a doctor. 1. Overwork: when walking for a long time, it may cause the muscles to be in a state of tension for a long time, without relaxation, which is easy to make lactic acid buildup, leading to local blood circulation obstacles, thus appearing edema, the phenomenon of the surface of the foot pain, generally can be relieved by appropriate rest to alleviate the symptoms. 2. Synovitis: It is usually a lesion caused by synovial inflammation due to a variety of factors such as degenerative joint disease and trauma. When walking a lot, it may irritate the local tissues, aggravate the condition, and appear the phenomenon of swelling and pain on the surface of the left foot. Patients can use non-steroidal anti-inflammatory drugs such as diclofenac sodium extended-release tablets under the guidance of a doctor to relieve symptoms. 3. Fasciitis: This disease may be related to overwork, trauma and other factors. When walking a lot, it may lead to muscle stiffness and stagnation, resulting in swelling and pain on the top of the foot. Patients can follow the doctor’s instructions to use compound chlorzoxazone tablets, compound salicylic acid methyl ester cream and other drugs for treatment. The patient appears to walk a lot of swelling and pain on the surface of the left foot, may also be related to the shoes do not fit and other factors, based on a symptom can not determine the specific cause, it is recommended to go to the hospital in a timely manner for examination.