DONT WORRY MAN! There's no need for concern. Alot of cars do that on startup. That's generally because rotors develop surface rust over night. Sometimes, it's just because the salt or dirt from the road deposited on your rotors. So don't worry about it.
If your breaks are squeaking all the time, then it's because you either have worn out pads (which might be the case for the rear pads) or it's because they're low quality pads without the noise reduction back plates. SOMETIMES, when you get your breaks changed, the mechanic doesn't clean the calipers with break dust remover and that might cause your pads to squeak all the time.