This is about my personal experience, but not asking for medical advice so I’ll try this in GQ.
When I get an acid stomach, I often find that the insides of my ears itch–the flat-ish part you can reach with a Q-tip, not all the way in (though I know you’re not even supposed to put a Q-tip in that far).
Why is this?
I’m interested, too. Mine don’t do precisely this, though.
When I drink something acidic, cold, and fruity, my ear canals will itch, too. I have to restrain myself from scratching them for a minute or two, and then the itching goes away.
The nerves which provide sensation to the ears can also provide some of the sensation for the lower part of the throat (the pharynx) and the upper part of the esophagus. So, if acid irritates the pharynx or the upper esophagus, the brain can misperceive the sensation as originating in the ear(s).