For 3 months I've had gastrointestinal issues: indigestion, stomach cramps, burning abdominal pain, fat intolerance, and weight loss. And this last month: yellow greasy stool, malabsorption, continued weight loss, (27 lbs so far) and stabbing joint (leg) pain. I am eating 2-3 meals a day, taking enzymes to help with the indigestion, and vitamin supplements, but I'm still losing weight. Gastroenterologist gave me an endoscopy that only revealed a small hiatal hernia. Ultrasound revealed no gallstones and blood work is normal. CT scan ruled out pancreas. The doctor said he doesn't know what is wrong with me. What could be the root cause of these issues?