These symptoms are quite alarming. Have you got any investigations done? do you get heart burn or pain in upper abdomen? where is the pain most often - Which area of abdomen? You could be having an ulcer in your stomach or duodenum(small intestine) or it could also be due to low sugar levels or inflammation of the Pancreas. I would suggest you get your liver function tests done as well as an Ultrasound abdomen and if they are normal then an Upper GI Endoscopy. But before that please reply with your sex, weight and location of pain and also whether you have ever had vomiting with or without blood or have had black tarry stools? Will wait to hear from you. Take care.