Have Irregular Period, Have Hiatal Hernia, Heaviness In Chest. Had An EKG. Fear Heart Attack?

Hi. I m a 47 year old woman, 5 2 and 265 pounds. (Yeah, I know.) For the past several months, I have been experiencing what I believe are gastrointestinal symptoms that are especially bad around my period - which are also slightly less regular than they d been all my life, and horribly heavy. The symptoms are just close enough to the kinds of things you hear about cardiac problems for me to be paying close attention: and I m trying not be an idiot and end up dead of a heart attack . My best friend, who is a vet, wondered out loud if maybe I have a hiatal hernia (after scolding me for not going to a doctor). After reading quite a bit about it, it sounds right on. These symptoms do NOT worsen with exertion when I have them, and do not lessen with rest. I do not have trouble taking deep breaths - but my chest feels heavy or a little tight: and that s much relieved if I apply manual pressure to moving areas of dull achiness, and that is usually accompanied by burping. I had an EKG a few months ago with a regular physical, and it was fine. My question is this: is there any way to confirm that this is gastrointestinal and not cardiac without incurring hundreds or thousands in medical bills? Because of my weight, the only insurance I can get is through my employer - and it s a catastrophic plan. My deductible is $7500 before insurance pays a penny. I d like to be able to send my son to college in a few years - and I d like to be around to see it. Thanks for any advice you can give me.