If government impose price control, what happens?
Those are all potential consequences of price controls. It would all depend on how the price controls were done, what measures were put in place alongside them, and all the context of the good itself.

If the price is set at too high a level, excess supply may occur. If too low, excess demand may occur. If it's a good with an extremely limited market that is met under the price control, then no unexploited opportunities may exist. If potential demand is greater than the rate at which it can be retailed, then people may spend a lot of time waiting in line to acquire the good. And underground markets may emerge in any case.