As a late coming utter incompetant in creating music I get totally confused by what chords go well with one another. I was told about an app which I never got round to buying called Fiddlewax Pro which cost about £15 (not cheap for an iPad app) which was made for students and other idiots.
The designer has just rebranded it with some updates and called it Firo. It is free until the end of July and is really well done. Recommended at twice the price! Seriously if anyone else is confused with this stuff check it out. If you don't like it you can always delete it. It dous as a midi controller/recorder too