I hesitate to comment on this serious issue, but I think the choking and swallowing issue is MS. I have had it in fairly mild form myself (on occasion badly) and have seen considerable numbers of MS people who have it, back when I went to support groups. I had it just tonight but I quickly recovered. Putting a tube down your throat--that is unpleasant, although if they knock you out you may be able to tolerate it. It was the only test I could not tolerate, and doctors have told me it affected them the same way. Since it is probably MS, I would suggest that it will simply stress you to go through the test. Of course, some other problem COULD be discovered with this test.

What they were trying to see, in my case, when I failed to be able to tolerate this test, was whether or not I had an ulcer from too much acid. Later, I found a doctor who does the Heidelberg test, where one swallows a tiny radio in a pill, which is later excreted, to measure one's stomach acid. I had NO stomach acid, so taking antacids was, most of the time, not a good idea. However, I could not tolerate the hydrochloric acid that doctor wanted me to take, to replace stomach acid, and went on to take digestive enzymes. I rarely have stomach problems now. My stomach area pain was in part due to Porphyria, another disease I have which was undiagnosed, and which was not diagnosed until years after my MS dx. In this disease, the nerves to the stomach (and other organs) can become inflamed and cause acute pain.
But I gather that is not your present problem, KittyLady--it's the swallowing the doctor is wondering about.