Nobody's a pain in the butt. We're all patients here. Just don't expect expert medical advice because we're not docs.
Your doc has probably never heard of "cardioesophageal reflex," aka "linked angina." My stomach and heart docs hadn't either, but that's what happens to me. I eat something I don't tolerate and a half hour to two hours later I can get tachycardia and arrhythmias. I can usually get it stopped with Valsalva maneuvers and coughing. I have some atenolol if it goes on for more than a couple of minutes, also take an aspirin in case it triggers a clot, which could cause a heart attack. I had an attack of diverticulitis that was starting in my sigmoid colon that triggered an attack of tachycardia and sent me to the ER. So nothing is too far away! Google some studies and see if anything sounds familiar.
I don't know anything about Ritalin. Maybe someone else will answer that one.
What med did they put you on?
Since it can take hours for a trigger food to start a reaction, just try keeping a food journal - times, everything you eat and drink, all meds, and write down reactions with times.
It would still be a good idea to get the esophagus and stomach checked out. Even though I've had the surgery for GERD I sometimes get a bout of nausea. My gastro doc has me take Nexium for a while, which helps a lot. Having a professional take a look can at least rule out GERD as a cause of your discomfort if it's a regular thing, maybe not so sure if it only occurs occasionally.