Recently i found myself lying down in bed and playing guitar for hours, is this a really bad habit or is that normal, i spend most of the time sitting up, but many hours laying down.
it really doesn't matter, just make sure you can play when you're standing up if you ever wanna gig. You hold your wrist differently when sitting and standing so make sure you can play when doing both
No, its just bloody uncomfortable (for me) and its a lot harder to reach higher frets.
You'd need a bed if someday you go for a live playing guitar, lol.