Vehicle runs and then you shut it off go to get back in and it won't run.

Bad connection , or faulty starter.

Sounds like the first thing you need to look at is your starter if your still having this problem then next time it doesnt start tap on the starter lightly with a hammer or some other object. it is possible you have a dead spot in it meaning you just have to bang on it and continue to try and start it. if this works then either have starter rebuilt or buy a new one

You might want to check the shift lever position sensor. If it isn't making contact it will not start. Try shifting it down then back up, emphasizing the push up. You may just have to jiggle it then see if it will start.