A solution to this problem occurred to me in the midst of a reaction much like what most of the people in this thread are describing. I realized that the pain I was feeling was essentially a severe, unrelenting hiccup (pain from sternum to salivary glands, and on the verge of vomiting after eating some rice) and so set about employing the most effective anti-hiccup remedy I know: a spoonful of straight sugar, swallowed as dry as possible. Relief was immediate. Yes, chewing the rice well helps avoid the esophageal hyper-reaction, but now I have a backup solution to the problem. Try it! It certainly can't hurt, as it is quite literally a placebo, only one that works (for me).