L.M.
Ibuprofen is the one that is tough on the stomach and acetaminophen is the one that builds up cumulatively in your liver. Take Ibuprofen on a full stomach to combat is ulcerating tendencies and alternate with acetaminophen (Tylenol) to cut down on the cumulative effects of that.
Also, keep in mind what kind of pain it is. Ibuprofen will help reduce inflammation, so if it is something like a twisted ankle, that would be the recommendation.
Feel better.