Wow - not paying attention to lupus can be very risky business! It's generally not a disease to take lightly, and it has a way of coming back and biting you if you ignore the symptoms! Encourage her to see a qualified rheumatologist (preferably) who has experience with autoimmune disorders like SLE. Chest pain in lupus can mean a lot of things (as Kimb told you.) Sounds like your GF suffers quite a bit from her flares - she could really benefit from some sound medical advice.
Prednisone is no fun - I want to be DONE with it myself - just as soon as possible! But, if she has symptoms that only respond to steroids, maybe she has to accept that for the short term? Kimb makes a good point, though - if NSAIDs will do the trick, I'd take that over the steroids any day! (Wish it worked for me.....)
You're a 'saint' to help her like you are....we all need an advocate like that in our lives!
"If you trust Google more than you trust your doctor than maybe it's time to switch doctors."