I sit in a cold room with ice where it hurts and try taking a pill like ibuprofen. If you can, try to get sleep cause then you can't feel it. Also I heard that light excercise, like stretching or yoga helps.
This will sound strange but it worked for me: Lay face-down on something soft (exercise mat). Position yourself so your head stays down, arms folded beside your body. Then pull your knees up so they are under your body and your hips are in the air. This takes some of the pressure off you spine and for some reason, helps with cramps.