Some good words from John MacArthur about Christians and singing:
The Spirit-filled life produces music. Whether he has a good voice or cannot carry a tune, the Spirit-filled Christian is a singing Christian. Nothing is more indicative of a fulfilled life, a contented soul, and a happy heart than the expression of son.
The first consequence of the Spirit-filled life that Paul mentioned was not mountain-moving faith, an ecstatic spiritual experience, dynamic speaking ability, or any other such thing. It was simply a heart that sings. When a believer walks in the Spirit, he has an inside joy that manifests itself in music. God puts music in the souls and then on the lips of His children who walk in obedience (Ephesians: The MacArthur New Testament Commentary, p. 256).