Cannot see iTunes Radio on my device after updating to iOS7
According to zdnet.com (today),


  iTunes Radio is only available to U.S. account holders at launch and is also available in iOS 7.


The article is about iTunes 11.1, but I presume the same goes for iOS 7.

Wikipedia (today) states:


  Currently, iTunes Radio is only available in the US.


TechCrunch (yesterday) has:


  Also remember that iTunes Radio is for U.S. iTunes account holders only for now, with no word on when international users will gain access just yet.