Abdominal pain from abdominal organs are not formidable to diagnose provided sufficient fund of knowledge and attention of the clinician.
Visceral pain is vague and diffused. It is very hard for pt to pin a finger on it. In contrast, pain from parietal peritoneum is sharp (like a needle prick) and well localized. The patient will be able to show the area of pain and pinpoint the most painful spot.
Like other pain, abdominal pain can not be interpret alone. Of particular importance is the accompanying symptoms or the lack of it.
General area of pain from upper GI tract