My iPhone won't autorotate

My iphone won't auto rotate and I am running 5.1.1. It was working fine, but now it isn't, anyone have any answers? Before you suggest anything, I have checked and done the following:

1. I verified Portrait mode is not locked by hitting the home button twice and checking to see so on the "Portriat Orientation is Lock/Unlocked button"

2. I have shutdown

3. I have reset using the home and power button.

4. I have verified this is happening in my facebook app, sunshine apps for my cameras and more. All of these have been working since I have owned the phone.

I am worried this is an issue with 5.1.1. My husbands app is working without error and he has the exact same phone and verision.