Joy is right. Food allergies, AKA sensitivities don't always show up on testing. Lots of doctors, including some allergists don't know much about
them and they can cause life-threatening conditions.
My particular sensitivity causes reflux and tachycardia. It's a known phenomenon called cardio-esophageal reflex. (not reflux) It works both ways. The esophagus (when triggered by various means, which in my case was a food trigger) can cause arrhythmias. The heart can trigger esophageal spasms. So you have to find out if you have an esophagus or a heart problem first.
In my case it was always the esophageal spasms and reflux that came first and triggered the heart.
My allergist had me keeping a food log for a month and then doing challenge testing to find the particular foods within a meal that were the offenders. I came out with a long list of unrelated foods, except for one thing - SULFITE. (not sulfate or sulfa) There is no blood test or skin prick test for sulfite, and the darn preservative/dough conditioner/bleaching agent is in a lot of stuff we eat all the time, particularly fast foods and pre-prepared meals.
I'm not saying everyone has the same sensitivity, but my problem is an example of how to find out if you do have a sensitivity that cannot be tested for in the office. I have posted my list of foods, and they can be searched in the forum, but you can also just google sulfite allergy or sensitivity and find pretty much the same list.