Good, keeping a food diary is a good idea. Also, eliminating all lactose from your diet for 2 weeks to see if that helps is a good idea.
Thank you for replying. I try not to eat too much after 7 pm as I am trying to lose weight. So I do not think it is what I eat. However, I will take your suggestion and take note of what I eat every evening.
Welcome to the gastroenterology community! I don't think you need to be overly concerned about this, but you might have some sort of mild IBS. This could be caused by a food-intolerance from something that you are only eating in the evening, which is why you are only getting symptoms in the morning (when you have digested it). For instance, do you eat a lot of lactose in the evenings?