What I could add is:
When you want to compose music what you need to do one way or another is to study music, but not in the sense that you have to go to the university or something. Just in the sense that you have to work with it in a conscious manner, trying to find out what works and what doesn't. Play around with your instrument, listen carefully and closely to different kinds of music, try to emulate the sound of something that you heard, learn from what others do with their instrument. These are all things you can do without learning to read or write notes or name chords or anything on top of that.