Acid reflux?
Never had quite what you're describing, but I used to get bad heartburn in the afternoons. I did some reading and found that the general recommendations included cutting back on (or cutting out) eating the following three classes of things:
1) Carbonated beverages - D'oh!
2) Fried food - D'oh!
3) Spicy food - Just kill me now and D'oh!
I cut back on all 3 and my (admittedly more mild) symptoms went away.
Not sure if this is related at all to what you're going through, but...it helped me!
John