I recently asked a pharmacist about painkillers and crohn's as I was getting a lot of headaches, which paracetamol alone didn't help.
I've found that the combined paracetamol and caffeine pills are more effective than paracetamol alone (the caffeine increases the painkilling properties of paracetamol), and the pharmacist also recommended co-codamol (500mg paracetamol + 8mg codeine).
If that is not strong enough you can try the stronger codeine combinations (500mg paracetamol + 30mg codeine), although they are prescription only in the UK. I can only take one of those at a time as they make me a bit spaced out, even when I have a lot of pain.
The problem is that if you then end up constipated by the codeine, then things like lactulose can be problematic with crohn's, and interfere with some crohn's medications.
I believe that any non-steroidal anti-inflammatory drugs (aspirin, ibuprofen, diclofenac, naproxen, etc) are not a good idea with crohn's. It's a bit ironic when inflammation is our enemy here!
I suppose, where lifestyle allows it (I have two kids, so not very often!), then curling up and resting with a blanket and hot water bottle is an alternative source of comfort, but that doesn't help when there's so much else to be done!
I'd also love to hear any suggestions from those more experienced in this area than me.