Sorry you're struggling! Do you think that perhaps some food is getting stuck at the wrap site, and causing irritation, and reflux feelings? If you have a very sensitive esophagus, it could cause even more discomfort. The acid/sour taste could be fermented food as well as some (normal level) reflux.
Doritos can be chewed completely more easily than chicken, as strange as that seems. I'm probably off base, but when I heard that normal chicken is harder on you than nuggets (created from chicken that is made liquid, then formed into nuggets) it seemed like it could be a consistency issue.
Be sure to chew your food slowly and completely--until it's a liquid/creamy consistency. Since you've had surgery after surgery, you've never had a chance to get fully healed. Because of that, I'm sure that you will take longer to get through the healing and adjustment stage.
I'm probably off base, but the thought came to mind, so I figured I should share it!
Nissen Fundoplication 2/09
"Whatever you fight, you strengthen, and what you resist, persists.”
“Worry pretends to be necessary but serves no useful purpose”
“Accept - then act. Whatever the present moment contains, accept it as if you had chosen it. Always work with it, not against it.”