There is no real way to tell when an abdominal pain requires urgent attention. This is because many mild conditions can also result in abdominal pain while serious conditions may be associated with symptoms other than pain. In general, if the frequency, intensity and duration of any episodic pain get worse, it is time to seek medical help.
For constant abdominal pain, the intensity and duration become important. Any pain that persists or progresses over time, especially when associated with fever or vomiting, needs immediate medical attention to exclude an acute or surgical abdomen.