ive taken one MAYBE two a day for a while (years) and even that is only if I have to. mostly when a migraine starts. I started taking B2 (riboflavin) about 2 months ago and now I take WAY less powders because I have way less migraines.
For body pain (mid 40's) I take aleve once a day maybe twice if needed.
My vote is the aspirin. I get a sour stomach ache just by taking two Bayers, kind of like eating green apples or something.
But be very cautious of any lower abdominal pain. Right side could be appendix but left/lower problems are a fairly common problem too called diverticulitus (sp?), which are irritations or actual weak sections in the wall, even pockets that can develop similar to the appendix. And they can also rupture causing infection just like the appendix.
I'm pretty sure it's the caffeine that triggers one to believe he needs a lot of headache powders. My brother worked with a guy who had to have one if he saw one in your truck. The body and addictions are weird.
The caffeine is the secret to getting the aspirin in your bloodstream fast.
I agree it's the aspirin irritating your stomach. Maybe ibuprofin and a cup of coffee would be better on a limited basis.