B.D.
You might want to see a chiropractor.
My husband had this problem and MORPHINE didn't even help, so don't let it get too bad.
A chiropractor can adjust the discs in your back and maybe relieve some of the nerve pinch. He/she can also give you suggestions on some stretches to help strengthen the muscles around without hurting the baby. Of course you want to go to a chiropractor who has dealt with pregnancy adjustments before. ;-)