My mum is at the age of 82, for the passed two years, my mum was having her right leg swollen, in the early stage, she felt her right leg was very stiff whenever she stood up or walked, recently she felt very painful whenever she stood up or walked, the pain can " moved ", sometimes at the right leg, sometime at the left leg and sometime at the back, so what will actually cause the pain ? My mum is having high blood pressure for over 20 years, but under good control.