Hello - these episodes are not predictable and inconstant. I have been to my FMD for a stress tests, chest xray, and lab work - results were normal. Symptoms are burning pain across my upper back, frequently with nausea, but rarely to the point of vomitting. Episodes last from a few to 10 minutes, and usually occur with exercertion, such as swimming or even walking. Symptoms stop with a brief rest. I don t believe it is musclar or conditioning, since I can walk for miles, and swim (albeit not fast) for an hour. This has been going on over the last year.