You are full!! The chest pain means you are full. You are vomiting because you are full. The new "full" feeling you will experience after sugary feels more like chest pain or air bubbles than the pre surgery full feeling like after a really big thanksgiving dinner. The reason it goes in cycles is because sometimes you are so full it may take a day or 2 for you to be "empty" again. You really should only be eating about 1/2 a cup at a time and listening for the soft cues. Hicc-ups or an air bubble feeling. All of the vomiting is not good for you.
Your best bet is to talk with your surgeron and let them know what amounts you are eating and what foods you are eating. Chances are you are feeling restriction and just don't know it.