Sit-ups after the stomach pain is a normal phenomenon, do exercise muscle will produce a substance called lactic acid, lactic acid can make muscle soreness, especially people who have not done exercise for a long time, once and do a lot of sit-ups, abdominal pain will be particularly serious. Before doing sit-ups do a little warm-up exercise, the pain will be reduced some, and then insist on doing a few days in a row, the pain will disappear. If you do sit-ups after abdominal pain accompanied by vomiting, diarrhea, fever and other symptoms, it is not a normal phenomenon, you need to see a doctor in time.