Speaking of memory foam, I once tried one of those mattresses which are made of that.
I lasted two hours before the intense pain drove me back to my old bed. I guess it's the way Jprinz described it with the memory foam pillow. One does not move much on those things, relaxing into a fixed position, and the reaction of cramping up can be awful. I had them remove the mattress the next morning, had to pay 10% of the mattress cost, but there was no way I could ever sleep on that. This was long ago.

KittyLady, please try some magnesium pills to see if that helps. My potassium tends to take a dive, too, if I don't use 20 MEQ potassium pills a day. I regulate salt carefully, as Jprinz suggests is needed, to get about 1500 mg a day, not too much and not too little.
Since you don't get the baclofen pump for a while, it might help to try some other remedies.

I had NO reaction to the spinal tap years ago. I could not feel it. I am wondering if I am numb in that area, or if the great neurologist was so good at doing this that I couldn't feel it. He was a brilliant man, the one who told me to take magnesium when I could not tolerate Baclofen. Baclofen made me run into walls--one pill and through with that. Zanaflex made my muscles too weak to walk, released too much spasticity. Maybe I needed a smaller dose, but the magnesium relieved enough spasm and jerks so that I didn't try drugs again, except for the small Klonopin dose. I might add that I also take calcium, but always at a slightly lower amount than the magnesium, and for me that is also necessary.
It scares me how close I live to being a jerking spastic monster. What if I can't get magnesium pills some time. I'll be nothing like I am now. I will need intense sedation.