To me, "stomach ache" is a very vague term. But, abdominal pain is quite varied in quality and degree. If I am having sharp, severe pain, then something is really wrong, like a partial obstruction or serious pouchitis. Or, maybe even an upper GI problem. Mild cramps and rumbles usually mean dietary issues or delaying a bowel movement (gas wanting out). IBS causes significant symptoms and there is no inflammation.
Anyway, you cannot assume every belly ache is a relapse and a calm belly is remission. I thought I was doing pretty good and still had severe pouchitis.
Jan