I have this same freezing problem, and it occurs in diverse apps as well as in the iPhone settings themselves.
I notice MANY complaints in the Apple Support Communities about this same freezing problem on iPhone 5s running IOS 6.01 and even the brand new 6.02. The standard response from the "experts" in the support community here -- to reboot or restore the iphone (or visit the apple store or call Apple Care) -- rather misses the point, in my opinion. So many iphone 5 users should not be having the same exact problem!
Instead of band-aid replies to reboot and restore or get Apple tech support involved, we need an actual lasting fix to this systemic problem, so the freezing stops happening for all of us.
The real question is this: What explains this too-common freezing problem on iPhone 5 running IOS 6x?
I believe that Apple has screwed up, plain and simple, by putting out a device and OS that has not yet been properly vetted. Seems that Apple has been doing this a lot lately (e.g., OS7x Lion, the Apple Maps app), and I suspect this is an internal Apple culture issue -- a pushback against the perfectionism of the late Steve Jobs, perhaps. If so, that's too bad for us devoted Apple product users as well as Apple's investors, quite honestly. I am unhappy to see Apple acting like Microsoft by testing new products on consumers. Apple Corporation itself needs to reboot and restore its "insanely great" standard of excellence!
Meanwhile, I am still looking for Apple to "get on the ball" by swiftly providing a reliable and permanent way to stop my brand new iPhone 5 from freezing constantly.