Samsung Smart Phone Started Asking For Non-existent Pin Code

I've been dealing with this super annoying problem on my Samsung phone that has me totally confused and irritated. So, get this, after I turned my phone off and on again, it randomly started asking for a pin code out of nowhere. Like, it had never done that before, you know? The thing is, I haven't even bothered to set up a pin code for my phone in the first place! I tried everything I could think of, but it just wouldn't accept any pin I put in. To make things even worse, it keeps popping up a message that's like, "...Give it another shot in a couple of hours." I've heard other people complain about the same thing. I really need help with this problem.  if anyone can help me out real quick, I'd really appreciate it.