Hearing Music in Your Head

Lately I've been thinking about giving up trying to become a musician and composer and just stick to being a hobbyist guitar player because of this very reason.

It is very frustrating to say the least because I have wanted to be a musician since I was like 4 or 5 years old when I first watched the movie "La Bamba" about Ritchie Valens. Wanting to be a musician has not left me to this day, but I absolutely cannot hear any music in my head (I assume you are talking about live audible sounds and not just the "thought" or "memory" of a particular sound.)

Every great musician and composer that I hear of always talks about how they compose or play what they hear in their head and that is something I cannot not do. I have written about 3 semi-complete vocal and chord tunes which have decent catchy melodies, but it was written from just winging it rather than me thinking "oh I hear this unpublished song playing LOUD AND CLEAR in my head, I better get this down".

I know I have great musical ideas embedded DEEP within me, but what good is it if I can't "hear them playing in my head"? I hope you know where I am getting at and if you can give any sort of advice short of paying money it will be greatly appreciated. Thank you.