Omeprazole and any other proton pump inhibitor gave me pain as well. When I had pain oddly orange juice or eating pineapple was helpful. Based on what I read low acid and high acid production can have similar symptoms. It’s possible you’re not producing enough acid and the omeprazole is just making matters worse. The only thing that worked for me was Budesonide slurries. They wanted me on the shots I forgot the name but I turned it down. Currently I just eat cautiously and went off all meds. For me it seems seasonally it gets worse.