Are you suppose to wait until the pan gets hot?!

If you are pan grilling or frying it is best to wait until the pan has heated. Some foods require a hot pan, others are cooked at low temperatures. Stir-fry requires a very hot pan for quick cooking, but foods cooked in a sauce are usually seared first than simmered. If you are just opening a can of soup, you don't have to wait for the pan to preheat; the food is already cooked and you are just reheating,

Yes, generally that is better, although if you are just heating up something from the freezer or something then no you do not have to.
If you are searing, sauteeing, or using a pan as a griddle, then it does need to be hot. Do not overheat non stick surface pans, they can be damaged by heating too much.

if you put it when the pans warm the juices get sealed in if u put it when its hot is doesnt, when u put it when its not hot it gives it time to cook properly and wont burn on sides, but it really depends what ur making.

depends on the type of food.

Pancakes require a hot pan to start.
Stir frying does better with a hot pan
But meals in a bag can be started cold.

the pan should be really hot.

It depends on what you are cooking...what might that be?...