What makes the iphone 3gs freeze constantly

Hi there and welcome to myLot! That could be a reason as I have a blackberry and whoa sometimes I have tons and it can run a bit slow, though mine has not frozen. I do know someone with the IPhone 3 G and he had a lot of freezing going on, his issue finally was that he had downloaded some apps that were conflicting with some of the functions so it would freeze. He had to remove one at a time, until he can figure out what was wrong. Then he re-downloaded the ones that were okay. The only other suggestion I can think of is perhaps your software, you get your updates frequently as they come out? Only reason why I say is that on my blackberry I did from time to time have issues and when I took it back to the store the first thing they would say is that I did not have the latest software. It was then I started to update mine routinely trough the desktop RIM. These are all suggestions and not sure if they can resolve your issue without technical support from your carrier.