I have had low back (left side) pain for four months. I have had my kidneys checked, have had an MRI, CAT scan with dye, x-rays, etc. Everything has come back normal. The aching is worse in the morning and keeps me from falling back to sleep. Sitting makes it worse. I have noticed that the pain goes out to my hip. I have also had blood work and was told my RA factor was elevated. I have no other pain anywhere else. My back does not hurt when I bend over, run, etc. Meds (muscle relaxers, etc.) do not work on the pain. I have been to PT and to a Chiropractor. Nothing helps. No one seems to know what the issue is but I wake up with this every day. One thing that is strange is that by night it is usually gone.