By the way, I forgot to ask you. Do you do anything to detox the aluminum from your body prior to this pain? If yes, there is a possibility the pain is come from the detoxification process.
"When aluminum comes out of its stored locations in your body it can act as an irritant. For example it has a tendency to irritate nerve endings which can irritate muscles. Therefore, when someone is detoxifying aluminum, there can be discomfort involved. And, since the kidneys are the organs that handle this detoxification, there may be pain in the back, over the kidneys, also."