Sudden explosion?

Alright so this night, i was sleeping and i came in some sort of a pre-dream thing, you know, when you are about to fall asleep and you start to see things but you're still half awake.
So, i was dreaming about stepping on my motorcycle, when suddenly i had the urgent feeling of that weird falling thing. Next thing i know is i fall asleep again and there is my motorcycle again.
So i step on the motorcycle and as soon as i put my hand on the left handle (which is not the throttle) i hear a loud BOOM, but this wasn't in my dream, but in real life. It wakes me up and at this moment i'm wondering what the hell is going on.. And even though it was just a noise in my head, i get the high pitch annoying noise thing in my left ear which continued untill i fell asleep.
This is the second time i've experienced such a boom.

Does anyone know what this is?

Thanks alot.

EHS is my first guess. It's just auditory hallucinations. My guess is that you are absolutely fine.