Yes, flares are as different for each of us as the disease itself is. It is almost impossible to predict a flare. Sometimes, the best that we can do is to take precautions in order to avoid a flare.
For me, my muscles begin to burn as if on fire and I get overwhelming fatigue (cannot move!). Generally, when I feel these things, it is followed by a flare which, for me, means mouth ulcers, debilitating fatigue, stiff and sore joints, loss of apetite, and extreme muscle pain.
Hope this helps