I was getting this bad upper abdominal pain after meals. It was almost always at night. It was usually about 1-2 hours after eating.
Trials of PPI (like Prilosec) didn’t help. Upper endoscopy didn’t show anything. It was really frustrating and I was worried something was really wrong.
I had a conference in Vegas and I noticed during the whole conference that I wasn’t getting that same pain. I deduced that the only thing different was that I would drink milk every night at home. And I had been drinking milk my whole life. So I took a break from it and my pain seemingly stopped.
A few weeks later I forgot and drank a milkshake and 2 hours later I thought I was going to die.
So anyway, you can develop these weird food intolerances later in life, with milk being a very common one. But there are others. See if you can simplify your diet and remove any triggers possible.
Maybe you have already tried this, but none of the docs suggested it to me and I was able to fix everything without spending any money. I hope you feel better soon and figure this out.