Sudden pain in a single finger can be caused by the following reasons: first, infection of the finger, when the finger joints or soft tissues are infected, there can be sudden pain in the finger, which can be accompanied by local skin redness and swelling and elevated skin temperature, which should be diagnosed by early physical examination, early oral anti-inflammatory and pain-relieving medication, and if necessary, surgery to cut and drain. Second, gout, when gout involves a finger, there can be a sudden pain in a finger joint, can be accompanied by gout stone formation and increased skin temperature, then the blood uric acid test and finger x-ray to diagnose. Third, tenosynovitis, when the finger has stenosing tenosynovitis, there can also be sudden pain in the finger, often pain in the joint, then early examination, early diagnosis, early closed treatment and surgery.