Locked screen lighting up when I'm not touching...and don't think it's a ghost

SOOOO I was just sitting doing my homework and every few minutes, the LOCKED screen would light up like I was getting a text message or something. I was excited because I thought I actually had friends who wanted to talk to me, but I became let down when I would look every time and there would be nothing except a pretty sunset or flowers.  I have a stable 3G signal at my house, so I don't think its going in and out of 3G. Should I be worried or does it do this to other people sometime? Could it be anything else? Should I call Ghost Busters?

Well? Huh? uh? hum? I've had several phones that did that every once in awhile?  It's like the phone needs to do something? & I'm not part of it!!  lol, Don't know, but some smarta, sorry, tech will come tell us? HELLO!!! 

this is just a hypothesis but i think it is due to the time being updated at 12:00 but im just taking a shot at the dark in that one but its really annoying when u are almost asleep and all of a sudden your room is all lite up

Your screen will also light up if you are charging and your battery is full.

I wasn't charging it and I don't think it was logged into an IM. I'm not that worried though. It's prolly nothing