It's been an issue for the past few years. However, it got to a point that I couldn't cope with it any longer. When driving from Chippenham to Norwich last week, I stopped at Maidenhead for a drink, only to realize that my lower back hurts so terribly and its almost impossible to bear the pain.
I don't think I'm that old
Sorry this is a late reply, I just saw the question...did you ever see a urologist to rule out kidney stones or any other kidney disorder.
Since this post was over a year old and no one answered you I answered too quickly according to what I had gone through. Tink is correct about problems with disks or possible arthritis and that should be checked out first.
It's most likely a disk problem, or perhaps arthritis of the spine, or perhaps osteoporosis, but as Ladyhorse said, urological problems should not be overlooked.
http://www.mayoclinic.org/diseases-conditions/back-pain/basics/causes/con-20020797