My rather refined Granny (she was a mill worker but married 'up') referred to any discomfort in your middle as a 'pain in the pinny'. Phrase was also used to describe someone who was a 'pain in the neck' or 'a**e'. She seemed to have an aversion to naming any body parts, substituting 'below' for anything in THAT region and made a classic statement that someone was 'showing too much of her Lady Chest'. 
Briefing against women ministers in Westminster
Walking sticks in "tottery" in old age
What’s a household item that reminds you of your grandma’s house?




Used in our house too when I was growing up and I never understood the reason (still don't)