Start with a factory reset and monitor it. Install your apps slowly so you have a chance to possibly identify a culprit. Also, try blowing out your micro USB port with an air can. You may have something in there that is causing the phone to think you're plugging something in. If neither of those get er done, you probably have failing hardware and I'd take it in to Sprint for service.
And if this is an occacional problem thats happening with your phone, bring it over to sprint then.
Being that it's not like its an Action, and its happening concecuentaly, then they will have this at fault.
As long as they listen to you clearly, because last time that i left my phone they didn't hear me, and where looking into the wrong thing ~_ ~
LWP = Live Wallpaper btw
I went into the Market to try to grab an AV to check the phone before I reset it. When I was there I saw there were a few updates to some of my apps. After I let them update, I rebooted the phone for good measure. It has been much better since then and only locked up 2x. I might uninstall each app I have and reinstall them one at a time. Shouldn't take that long.