My Friend Is Complaining Of His Stomach Feeling Sore..all Over

My friend is complaining of his stomach feeling sore..all over and says it hurts to touch it. His appetite is good..but soon after he eats he has diarhea...He doesnt have a gallbladder anymore. Im very worried about his health. He hasnt lost weight or anything..but the constant bathroom trips raise a flag with me. And why the soreness?