my iphone 5 was switching between silent with vibrate mode to increasing volume on its own. what could be the cause? solution?

i have an iphone 5. when i put it onto silent (with vibrate) mode, sometime later it would vibrate and then show volume increase automatically. felt the vibration in my pocket and brought this issue to my attention. i also noticed a spinning wheel next to the blue tooth signal on top of the home screen. what could be done to resolve this issue? thanks