Hearing Music

I have to sleep with noise or I just can't sleep. I sleep with a loud fan. Recently, I have been hearing music even with the fan on, but not all the time. The music sounds like a transistor radio, I can't quite make out either the melody or the words. In addition to this I had an experience the other night which scared me. I awoke to what sounded like someone trying to breaking into my back door. The noise was not someone breaking a window or someone kicking it in. The noise was like someone trying to slide the doggy door over. I sat awake for quite sometime waiting for a shadow of someone in the hallway, just in case and was relying on my dog to attack, nothing. I passed it off as dreaming. This morning was a different story however; I woke to someone saying "hey" not once but twice. I kind of woke and heard the person say something else, I couldn't quite make out. I sat there for a while, thinking maybe it was my dog making a noise in his sleep but didn't hear anything else. I told my boyfriend when he woke to get in shower, which of course he laughed off. I got up to make bed and saw something walk down the hall, thinking it was him I looked down the hall he was still in the bathroom. Is this my imagination? Are these two instances related? Someone told me that when you see someone out of the corner of your eye, such as what I kind of saw, this could be my spirit guide. Is this true? I have had this happen when I'm stressed in the past but I never had anything try to communicate with me. What could this be?