My car would magically not start for 15 or 20 minutes after short trips...sometimes. Sometimes if you wiggled the key around it would go ahead and start. I ended up being stranded a good dozen times over almost a year. Then, finally, it got so that you couldn't count on it to start up again.
I took it in to my mechanics in MO three times prior to moving. After moving, I took it in twice here. Each time I was told that they couldn't find anything wrong and that I'd have to wait until the car was acting up and let them look at it then.
I ended up having to have it towed twice in three months because the problems were a bad starter (which was less than 6 months old when this whole business started) and a bad ignition.
It was one of the most annoying things I ever experienced!
Here's hoping you can get this solved quickly so it doesn't cause any further problems for you!