I know it is frustrating to not have a cause because I am there with you. Consider asking your doc about fibro. I heard from mine that the treatment would be different. Also I agree my magnesium is my favorite supplement. I take glycinate form. I also feel the role of calcium and d as a person with osteo is key. I am assuming you are a guy but did you have a bone density?Can't one just get pn without it being from something or is this not true? I thought a lot of people with age have it. Obviously in my case that is not it. Lastly my first emg/nc showed nothing then I went back and had another plus an ssep and it showed the pn. Not sure if it was too early to show or if the person doing the test was off. Who knows.Hang in there.