this may sound silly but it sounds llike trapped wind thats causing your abdomen to swell i had somethink very similar to this and it was jst trapped wind lol
Hi Erica~Sorry that you are having pain.
It seems to me that you could be having a little bit of gastritis, it could also be related to your appendix. If it continues to get worse, then I certainly would see your doctor, you don't want a ruptured appendix to deal with.
Take care and God bless.