Just saying gastric problems doesn’t really convey much.
As far as the acidity look up omeprazole, I think there is an over the counter version. Long story short I spent years eating antacids like candy, all day long and would woke up in the middle of the night for more. On a checkup my doctor gave me omeprazole and overnight my problem was gone. Heck I was supposed to take it daily but from the get go I only needed a pill weekly if that much.