What Causes Left-sided Stomach Pain Radiating Towards Rib Cage?

for the second time in 3 months, I have had pain that begins on the left side of my stomach near the rib cage. Then, it is in my back at the same area. Is not sensitive to touch and is localized - can move, bend, etc. without issue. Have been to the docs - first time ordered xrays of chest and back - nothing. Also, urinalysis was normal. Will have an MRI on the 22nd. Shingles was ruled out; and now, they think it might be a pinched nerve. Pain is dibilitating, and ibuprofen has been taken (up to 2200 mg a day) without help. At onset, I was either just sitting or standing. I am 65 years old, exercise 4 days a week (strength training 2 days, combo 1 day, yoga one day) as well as moving most of the day. Also, when pain begins, start sweating, then become cold until pain subsides. First time, that was after 7 hours, this time over 15. Although pain subsides, is still there 2 days later. Pain is about a 7 or 8 on a scale of 1-10. I feel if it is a pinched nerve, I should have been doing something at the time, which I was not. Have baffled a physician s assistant and doc, so far!