How do i tell the difference between gallbladder pain & constipation pain?

Difficult: to tell without a medical history, physical exam & some tests. Usually gallbladder discomfort occurs a few hours after eating fatty or greasy foods with upper abdominal discomfort & nausea. Constipation can be various cramping feelings with cramps anywhere in the abdomen, not related to eating. Ultrasound tests the gallbladder. History of lack of bowel movement is constipation.