Stupid title i know

Today my N900 kept doing one small (half a second) vibration every 5-7 minutes, It's also getting a bit warm for no reason. No apps running in background, no alarms set, nothing.

It just does a small vibrate suddenly every 5 minutes, and the screen doesn't light up, nothing appears on screen when it vibrates.

I rebooted and the problem still exists,so what going on xD?