Nasty when it's like that. Remember lots of us have been there and not only survived, but learned to cope with it. All everyone has said about heat, pillows etc. is right. When very bad you can try getting on hands and knees and gently arching your back. Another way is to lie on the bed and draw your knees up to you chest (you'll need your arms). Sometimes this can release the nerve, but it will always stretch the muscles. I must stress that in both cases you should warm your back first and do it very, very gently. Hope it feels better soon. Have you got a heat lamp? That often helps.