Did you get the phone brand new, or used/refurbished? I'm guessing the latter, in which case the previous owner probably rooted the phone.
If you have a Google account, you automatically have 15 GB of free Google Drive cloud storage. It's a good idea to take advantage of it in the future! You can also get unlimited backups for your photos in Google Photos, as long as it's set to High Quality (and not Original Quality):
https://support.google.com/photos/an...DAndroid&hl=en
I'm still not quite sure what you mean when you say that the phone tells you your System UI when you plug it in. What do you see? A screenshot would be helpful:
http://forums.androidcentral.com/gen...d-central.html