IMessage is not working with iOS 6?

On Friday, I got a new iPhone 5, well, later on after I had synced it to my computer and everything, I decided that I would turn on my iMessage and FaceTime. I went to iMessage in my settings and it said, "waiting for activation," so I tried to activate it, it said, "Could not sign in. Please check your network connection and try again." I had 4G and four bars of service. Why won't it work? I've "reset all settings" like twice.
Then, when I open Snapchat, an alert pops up saying," Connect to iTunes to Use Push Notifications. Snapchat notifications may include blah blah blah." No matter how many times I press OK, it will NOT go away.
The same thing happens with a lot of my other apps every time I open them, but they go away after I press OK. I'm just not getting any notifactions which is very annoying.
Can someone Please help. I've synced my phone countless times and looked on so many forums and nothing has worked.

Added (1). There isn't anything wrong with my backup?

IMessage typically has maintenance done on it. This is why I use iCloud for back up. Less hassle. Less problems. Maybe try that?

You have something strange going on, I've had no issues with imessage.

  • My iMessage on my iOS 4 (updated to 6) isn't working.how do I fix it? I was messaging and then it stopped working… I thought it was my Wi-Fi so I turned off and on the Wi-Fi, and still didn't work, so I restarted my iPod, signed in again for iMessage, and tried sending a message but it didn't work, and some contacts I have who do have iMessage on their iPhone/iPod it said they weren't connected to iMessage. Any help on how to fix this?
  • My iMessage is not working on my Iphone 4 I got the iPhone 4 around 3weeks ago.iMessage was working just fine until today. My texts were not sending at all. I have no idea how to fix this. I tried restarting my phone and resetting it and it didn't help. Someone please help! Thank you! I have tried everything! It is working on my friend's phone though so why not mine?
  • My iMessage for iOS 7 isn't working anymore but texts are.please? My boyfriend can't receive any of my iMessages and I tried restarting it. It said it was not delivered. Then it all of a sudden changed to text messages. My iMessage is even on. Can someone please help me! Everyone else that has an iphone can get my iMessage but he can't. It's happened to me with other people. I just don't know what I did
  • Is iMessage still not working? I have an iPhone 4S On my settings it shows that iMessage is activated. But when I text iPhone users it's still green. And I don't have the 3G at the top left corner. I'm just wondering is it still not working? Anyone experiencing the same thing?