We've had a couple of threads in the past about this aspect of songs and tunes. It is an interesting topic. I am a definite melody person. I sing and play recorder. However when I started attempting guitar I wanted to learn chords so I don't play melody on guitar, I strum chords. It makes for a different approach harmony. I have several times come up with some lovely harmonies to a melody but they don't go with the chords that are being played to the tune. I tend to see chords as coming after the tune and as being alterable, whereas others seems to see the chord structure as a solid and unchangeable foundation for the melody.