When I was having these exact symptoms it was related to the water I was drinking from my kitchen sink. I had just purchased a new home (the house itself was built about 10 years ago) and I was drinking water from a tap that had an in-sink filtration system. I developed horrible stomach issues (burning, cramping, acid reflux) and then the same burning/puffiness under my eyes. It took a few months, but I eventually tracked the root cause to the water and then switched to drinking only bottled water for a few weeks and all of my symptoms completely disappeared. Obviously I had the filtration system removed and changed the faucet, but I am still a bit afraid to drink out of my tap because the pain I was having was horrible. I don't know if there was bacteria in the faucet itself? Or if the filter was toxic or had something like bleach in it (?) I really don't know -- but that was the root cause of my issue and I am now totally better. I am so sorry you are having this issue because my doctor was completely clueless and it was so frustrating ... I also had all the same tests you've had and everything came back normal, even though I was in blinding pain. So I would say -- at minimum, something is definitely irritating your stomach and I would question absolutely everything you are consuming in your home environment and also maybe, notice if you start to feel better when you are vacation? Good luck and I hope this information leads you to the root cause of your issue!