Very possible. If you have a history of lupus, diffuse joint pain can certainly be a signal that lupus has returned. I would seek the evalutaion of a rheumatologist very soon to help prevent futher problems and of couse treat your joint pain.
Maybe. Joint pain is a common symptom of lupus and if you have previously had lupus flares which featured joint symptoms it may be reasonable to assume that this is lupus. However, as you can imagine, joint pain may occur due to a number of other reasons. An evaluation by a physician will determine if this is lupus or if there are other concerns.