It's kind of a tough question and I don't have any sources to back up what I'm about to say...but I think flare ups just go with the territory of CRPS. Flare ups for me always involve increased pain...but they don't actually involve the burning pain (that is what I have ALL the time)...when I'm in a flare up it actually becomes a bone crushing sort of pain where I feel like my bones in that area are being ground down to dust...it's so awful.

But pain isn't the only thing that happens to me in a flare up. Swelling increases, temperature changes occur, I get dizzy/lightheaded (due to my BP going wacky...something the sympathetic nervous system controls and in a flare up it goes nuts), my balance gets bad, my hand claws up and I can't uncurl my fingers (when I get a flare in my hands)...a flare up can basically cause ANY of your symptoms to be increased. If pain isn't one of your main symptoms (you are so lucky) then a flare up could just be an increase of other symptoms you have.