1998 Chevy Astro

Need better, more descriptive information. You say that when in park, "it doesn't go" What does that mean? It won't start? It won't do what.

When you say "go", does that mean the engine won't start? It starts but doesn't do something else?

Automatic transmission vehicles have a plastic start Park/Neutral safety switch. Usually, if the vehicle no longer starts in park, the shifter linkage has stretched to the point where it no longer makes the switch in park. It is a simple adjustment.