Common causes of sudden and unbearable pain in the abdomen include urinary system diseases, digestive system diseases, gynecological inflammation and other causes. 1. urinary system diseases: if the patient suffers from stones, there will be sudden pain in the abdomen, frequent urination, painful urination, and in severe cases, hematuria and other symptoms. 2. Digestive system diseases: patients suffering from acute and chronic enteritis, acute and chronic gastritis and other diseases, there will be abdominal pain, nausea, vomiting and other symptoms. If the patient suffers from appendicitis, there will also be pain in the abdomen, usually in the lower right abdomen. 3. Gynecological inflammation: If it is a female patient, it may also be caused by pelvic inflammatory disease, uterine adnexitis and other diseases. There may be other causes of sudden pain in the abdomen, it is recommended to go to the hospital in time for relevant examinations, to clarify the cause of the disease, under the guidance of professional doctors for treatment.