Chest Pain after Drinking Decaf - Encore

I wrote about unpleasant reactions to decaf coffee before. I switched to organic brands at home, or sometimes Folger's, which did not bother me. I also started brewing through an unbleached filter instead of using the French Press, just in case the oils were a problem. I did okay with decaf for a while, except for a couple of less-than-pleasant cups when eating out. (Some I didn't drink; it was too bitter. I like strong but not bitter.)

Then yesterday I tried a Seattle's Best Decaf for the first time. (It was at least "fair trade.") I bought it at a store which did not have an organic brand.

Big mistake. First of all, the coffee was bitter. Although it was not labeled French Roast, it had that burnt taste. And a few hours later, I started having chest pain. At first I did not relate the pain to the coffee. I didn't even remember that I had just opened a new kind of coffee yesterday evening until I woke up this morning and thought about fixing coffee.

"Oh, no. All I have is that bitter stuff," I thought. Then I made a connection. The chest pain was like I have had before, usually after drinking flavored coffee or some restaurant coffee.

And last night I lay in bed in with my chest hurting. Then the pain moved into my left side, inflaming an area from my rib cage to my waist. In order to relax in hopes of going to sleep, I entertained myself with trying to imagine what color the sore area was, and then changing the color. Eventually I slept.

In the morning, I still felt some pain but it disappeared after I got up and moved around. I still don't know why some coffee gives me chest pain.

Articles that may have clues:
Today I read that Seattle's Best is one of the brands that still contains caffeine even though it is labeled decaf.
Read about Decaffeination methods at Go Ask Alice or Wikipedia.
A 1985 article says that General Foods used methylene chloride to remove caffeine from its Sanka, Brim, Maxwell House and Yuban brands; Procter & Gamble used ethyl acetate to decaffeinate its brands: Instant High Point, Decaffeinated Folgers Crystals and Decaffeinated Vacuum Folgers. This may have changed.
Another article: Decaffeinated not Decapitated.
FDA says furan and acrylamide are found in many foods including coffee.