Lupus and backpain

I have been suffering from lower back pain the past 4 days with it progressively getting worse. I have been taking anti-inflammatory tablets and have an appointment with the physio tomorrow. I can barely walk. It is a burning pain and makes no difference if I am sitting or standing, it is quite sore. Is this related to the Lupus or something else? I have also been told I have fibromyalgia but this is the first time my back has been affected, normally it is my forearms, upper arms and thighs. Anyone else experience this and if so, what helps? I have yet to see a rheumatologist so am not taking any meds expect Vit D, Calcium and Fish Oil, as well as the anti-inflammatory tablets as needed.