Pain and swelling of the side of the fingernail may be overworked, but also may be related to trauma, infectious lesions and other factors. 1. Overwork: pain and swelling of the side of the fingernail may be overworked and overstretched fingers, resulting in fatigue inflammation of the finger muscles, joint capsules and ligaments, leading to congestion of the side of the fingernail, triggering the symptoms of pain and swelling. 2. Trauma: when the patient’s fingernail side of extrusion or trauma and other traumatic injuries, it will lead to increased permeability of the local tissue capillaries or rupture, if the tissue seepage can not flow out of the body, the nerve is severed, the symptoms of pain and swelling will occur. 3. Infectious lesions: pain and swelling on the side of finger nails are common in purulent dactylitis, inguinitis, osteomyelitis, due to various reasons that lead to bacterial invasion of the fingers and infectious lesions, which can cause swelling and pain and thickening of the fingers. If a localized abscess develops, the above symptoms will be more pronounced. In addition, pain and swelling on the side of the finger nail may be due to other causes, so it is recommended that the patient go to the hospital to determine the cause of the disease and then give targeted treatment.