Hi I also have bone pain seemingly unexplained. until recently. I went to clinic to complain about a bump I had on a toe that would not heal, and he discovered i had high blood pressure, and ordered a bunch of blood tests, one thing he clicked off was PTH which is parathyroid hormone.. you might want to read up about this. The parathyroid controls calcium levels in your blood.. sometime this glands become overactive and raise the blood calcium levels too high, thus causing the body to suck out calcium from your bones, this can go on for years with you not knowing... and causes a host of other problems, like high blood pressure, Osteoporosis, kidney stones, and or kidney failure, heart problems etc...
Since it is such a rare random thing.. it might just be your problem
Marz