Hello~It could be due to food sensitivities or even GERD. I know with my hiatal hernia, if I eat before bed, I get lots of acid reflux, but, it can also manifest itself other ways as well. Folks can develop allergies to food sometimes over night, you see, our system changes every 5 years, so, what you could handle one time, you may not be able to handle the next. Add a good, high potency, pro-biotic to your diet, this might help put the friendly bacteria back in your gut and stop those pesky feelings.