Phil, I don't remember if you mentioned this but have you had any testing of your hip?

I have a cyst in the socket of my hip. A simple x-ray detected it and would be a place to start. Before I found out I experienced many of the same symptoms you are describing.

An MRI would look at both soft tissue and bone and could be done if the x-ray doesn't show anything. I would also get an MRI of your spine if you haven't already done so.