What motivates people to "do" theology?

Having a hard time believing in God is what motivates people to "do" theology. Working out one's belief is really a good thing. Let me assure you that God is working with you. In the Letter of Paul to the Philippians 2:13 we read that "God is the one who, for his good purpose, works in you both to desire and work." I encourage you to read the whole of that epistle where you will find much to help you in working out your struggle of faith.

What does it mean to "have good morals"? For "everyone" to have "good morals," there must be a common understanding about what that means. Such commonality is essential to community. This is where the Canon of Scripture comes in - reading scripture together helps us share something common in our imagination; it will help each of us in how our conscience is formed, which in turn will influence our moral life. Working toward agreement will be hard at times, but such work is the mark of maturity and will be very beneficial for right relationships to develop.

I do hope you make Scripture reading part of your daily life. Read the Bible yourself, then integrate that into your relationship with others through questions and discussion; find people whom you trust to be wise regarding their understanding of Scripture - this is a major reason why "going to church" is so important. The Catholic Church presents herself as a trustworthy environment for working out what your believe with others.

In any case, don't do this alone. Having been given the Word of God in Sacred Scripture, we are called to be Christian disciples in community as the Body of Christ (and in turn benefit from the wisdom of Sacred Tradition). Alone you really cannot completely conceive what the call of Christianity entails. At some point, you need to humble yourself and learn from the conceptions of others, and especially from that One Other, Jesus Christ whose Holy Spirit guides us into all truth of knowing Father God.