Chocolate can cause GERD symptoms too. If you are having food triggers it would be a good idea to start keeping a food log (or journal), with symptoms especially within 2 hours after eating.
A lot of people have reflux, or migraines, or other symptoms after eating certain foods (trigger foods). It's food sensitivity, aka intolerance, aka allergy. I get reflux, stomach heaving and tachycardia from a whole list of foods. The thing my foods have in common is sulfite. Others have MSG or many other things.
My tach is because the heart is connected to the stomach and esophagus by the vagus nerve, as Joy mentioned. My foods are generally processed things like soy, corn products, french fries, gelatin. Sulfite is a softener, bleaching agent, preservative, dough conditioner.
I'm not saying food allergy is what you have. I like the gallbladder idea too, since chocolate stuff has a lot of fat. But keeping a food log will give you a list - which could be fatty foods.