Here’s a nice 4 minute video explaining how aspirin and iburpofen work. It’s interesting that these two work in the same way, more or less. I’d like to also know how paracetamol works, because that works well for me while the previous two don’t. Another thing is, can you develop long term tolerance to these painkillers? These questions aren’t answered here, but the video is pretty good for answering the main question — how do painkillers work?