Hi. Thanks for your query. Noted the history and understood the concerns. At the young age the cause of pain in upper abdomen particularly after eating and causing weight loss due to less food intake is usually due to acidity related problems like gastritis, duodenitis and so on. Hence I would advise you the following in such a situation: Get an appointment for consultation with a Gastroenterologist for clinical evaluation, examination and investigations like Upper GI Endoscopy. Till then you can take a PPI like Omeprazole, antacids when on empty stomach. Soft bland diet. Small frequent feeds. Avoid stress and anxiety as is common at your age. All these points together should help you solve the problems.