Kanga-
I don't like uncontrolled pouchitis, but I don't think of it as particularly painful. I wonder if that pain you're have is from something else, as you suggested.
Many folks seem to get help with pouchitis from a strong probiotic like VSL #3 DS. I use it at a maximal dose (4 packets daily), and I think it makes a real difference. I don't think fish oil is likely to do you any good at all.
Some folks report improvement in pouchitis from reducing carbohydrates (starches and sugars) substantially. I haven't done it, though.
Good luck!