Just Lately I Have Had Issues With Walking. The Bones

Just lately I have had issues with walking. The bones in my feet feel as though they are crunching together, I struggle especially if I have been on my feet a lot during the day, my knees also ache. I have had X-rays which show nothing amiss. I am 59 years old, female and slightly overweight. The pain is awful when I have been sitting for a while, I then struggle to get going. Walking upstairs feels like I am hugely heavy and I struggle to drag myself up the stairs. My GP doesn't help at all,