There's a heck of a lot which can go wrong with the digestive system, some things are only now being identified.
My DH has recently, after years or problems, been diagnosed with BAM - Bile Acid Malabsoption. Often previously diagnosed as IBS. The test is new and still unavailable in the USA. It can't be cured, but can be managed and our lives have improved considerably!
I had the dreaded endoscopy (not as bad as I feared) before Christmas and what I'd suspected was an ulcer turned out to be a small hiatus hernia (apparently very common in 'older' people - especially those slightly overweight - ie, me) and Barratts disease, which I had to look up (also common in the over 60'), and which has to be kept an eye on as it can develop into cancer.
So please, if you're worried about your indigestion do get it investigated.