What can I do for extreme gas pain in upper back, chest, and shoulders?

Maybe it's not gas. A person with "extreme gas pain" in the upper back and chest may have something other than gas. If it is gas, then taking an over-the-counter antacid/anti-gas medication should help quickly. But what if it is a heart attack or an aneurysm of the aorta? Those can be fatal, so a person with such symptoms should see his doctor or get checked at the emergency room right away.
Oxidative stress. Check my book on meridian medicine available i'n itunes. To understand eastern medical view - with large animal protein meal, kidney energy seperates into blood energy and compressed oxygen energy. When blood energy reverses flow the interference field results in inflammation. When compressed oxygen energy is reversed (oxidative stress) the resultant intereference field causes neuralgia - to rx.