Getting rid of loads of toxin can cause mineral deficiency. During the entire cleanse one should supplement in magnesium all through. I would even advocate to carry on after healing to avoid falling back.
Upper back pain is related to liver malfunction, mostly : Potassium deficiency
Lower back pain is otherwise related to adrenal issues: vitamin C will help and I would personnally say that candida can be summed up with adrenal issues related illnesses