2004 Toyota Tundra Stripped spark plug threads

I was replacing my plugs yesterday. I went to pull off the coil to one of the plugs and the spark plug came out with it. I thought, "ok, maybe the spark plug was loose?" I went to install the new spark plug and couldn't get it to "bite" into the treads of the engine block. Sooooooooo - I'm considering either:
1. Using a Heli-coil kit to repair the threads.
2. Considering taking the heads to a machine shop and get done the right way.