I should add that the meds I was on that goofed up my bowels was Ativan, but lots of diff medicines can cause your indigestion.
I'm about your age, and a few years ago I was on a medication that goofed up my digestion something awful, had diarrhea daily for six months, tummy bloated up, and I had your same lower cramp type feeling. I was given hydrocyamine for when I felt that crampy digestion, and once I got off the meds, my tummy went down. Another thing is, if you've just finished some antibiotics, that can stop up a person, so drink Acidophilus milk for a couple weeks, it restores the normal bacteria in the guts.