Sledge hammer

Is the post plumb as is?

Why does the post need to move? Was it built/installed out of whack? If something caused it to move and the track was fixed to the post it should've moved with it. If the post moved but the track did not then whacking back in place shouldn't affect the track at all. If you're trying to move it forward a pry bar might get you some of the way there. I vote for the sledge hammer.

That track should clear the block, assuming that is how was originally installed hard to tell from this picture.

Look closely... the track extends down well below the sill. The track must be attached to the post or the door raising or lowering would be free to move front to back..

The question remains, "Is the post plumb as is"

This is the way I frame for the garage door