Welcome to the Support Communities!
Are you experiencing the same behavior after restarting and/or resetting the iPhone?
I restarted and reset the phone and the same behaviour in the app store continued. Just a few minutes ago, I checked the app store updates and it showed none. I went back in no more then 30 seconds later, and 5 updates appeared. I went back in a few minutes later, and they were gone again. This is extremely frustrating.
This is definitely a result of ios7 and the app store, as I am also experiencing problems downloading apps that I have not previously purchased. I get the message unable to purchase, please try again later. However when I kill the app store from the background and go back in seconds later, the app appears in my purchased section and I have to redownload in order to get it on my device. In order to download an app I have to go through many steps as the basic buy, enter password and dowloading begins, doesn't seem to be happening. However, when I try to redownload a perviously purchased app which is not on my phone, it works without a problem.
When I first downloaded ios7 I was unable to enter my user id and password anywhere. I could not get facetime and imessage to sign in, so I did a full restore to factory state and then restored from backup and I was suddenty able to log in, but now I have this app store problem.
Thank you for using the Apple Support Community. Due to the nature of your issue or question you may find more information by using another one of Apple's support resources - https://expresslane.apple.com/GetproductgroupList.action.