Hi welcome though sorry about this. I am not as knowledgable as many here who I think will come along to help.
Did you have any fall in the recent years,any other health issues prior,were you active,sickness,meds you were on,etc? Anything you can think of in the past that is not normal or you may have brushed off but now could be connected? Have you seen any other specialists like rheumatologist or endocronolgist?