severe lower back (kidney area?) pain upon awakening

I am a 64 year old female.  for the last 3 or so weeks I have severe pain in lower left back area in getting out of bed in the morning- which feels like a muscle cramp and then severe pain upon trying to stand to walk.  I experience great pain when walking those first few minutes (I actually walk stooped over for the first few minutes) then rest of day no pain at all.  Does anybody experience this?  What have you done to help?  Thanks for any advice.  I am planning to see my primary dr tomorrow.