Yes, inflammation from Lupus can show up anywhere - I wouldn't be surprised to find it in the stomach. Even if it's not related, ALL symptoms you experiance should be reported to the dr. Drs are trained in what symptoms are important and relevant ..... we aren't!
So we need to mention everything we can think of.
I also think it's important not to "diagnose" beforehand -- let the dr do his/her job, don't go in and tell them what you think it is.....that gets everyone off on the wrong foot, most of us have found.
Good luck, hope your rheumy is a good one!