I use tiger balm for my stomach for exercise and sleepign when im feeling a bit iffy. Its mentholated so cools the area and reduces the pain for me .. their tube stuff is hot so works great as well (very much like deep heat and firery jack .. just make sure it doesnt go near any "tender" parts)
NSAIDs cause inflammation to those with GI problems. I'm not exactly sure why, but I know that it causes some people to bleed and I am apart of that group unfortunately.
It is because the active ingredients in these type of medications have the potential to cause ulcers higher up in the GI tract, stomach and duodenum, and bleeding. These are the side effects for people without IBD so for those that do have IBD the risks are far greater.