What is the % of getting paget's disease of the bone if there is a family history and have symptoms that could fit?

Cannot estimate: No one even knows what percentage of older folks actually have some paget's lesions, since the disease is usually subclinical. If older folks with an unexplained elevation of alkaline phosphatase are assumed to have paget's, it's maybe 10%. The key is that paget's can be managed nowadays and of course it's largely hereditary. Let your physician know of the family history.