Yesterday, out of nowhere, my lock button started to mess up. I would click it a few times before it finally unlocked/locked the phone. Then it wouldn't work for about 10 minutes at a time, then it would work again for 5 minutes or so, then 10 minutes unresponsive. Then, it stopped working at all. This was about 24 hours ago that it became completely unresponsive. Still hasn't worked since, I have to plug in the charger to get it to unlock. I have tried numerous times the battery pull method, but it hasn't worked once. Any ideas?