truck dies

What is your question?

I crank my truck up and let it warm up every morning, go to the store, then go to work. For the past two weeks my truck has been shutting down when I put it in park. When I am idling at the red light it is fine, but the minute I stop and put the truck in park it dies. Just had a tune up and it was doing this before the tune up, and stopped for a couple weeks after the tune up. Now it is doing it again. I am at a loss.