Brian, I too had a micro-d at L5,S1 in August of 04. Alot of what you are experiencing I can relate to. What others have said about your nerve "waking" up is true. Think of it like this, if you slam your hand in a car door, all is not fixed by opening the door. Your hand is still smashed. Your nerve has been compressed for a while now and it does not just bounce back. It takes alot of time. Your nerve is conducting signals between your leg and your brain and due to the injury, the communication is garbled. Your brain interprets the garbled messages as pain and senRAB back signals that your leg interprets to cramp your muscles. The Soma you were prescribed should help with the cramping. If not, there are other muscle relaxers available.
I was under strict orders after my surgery not to sit for longer than it takes to eat a meal, otherwise I was to be on my back or standing. Sitting puts more pressure on your back than standing or laying. You should also be walking as you can tolerate. This is great exercise for your back.
Above all, don't lose hope that you will have a successful surgery. I missed two months of work and had some setbacks but I have been very happy with my results. I have not posted on this board in about 6 months because I have been out living my life again. Hang in there, things will get better.
Alan