You don't know any music theory, but would love to compose more harmonic chords in Live? If you have Max for Live, you could use the Schwarzonator or Nordmann's "Chord Generator". While the former has some rather esoteric names for the presets that are not always very musical, the latter is based in music theory and even makes it visible. Both still require you to have an ear for harmonies though.
"Chord Generator" is a Max for Live MIDI effect that lets you create triads (3 notes) and tetrads (4 notes) by pressing only one key on the keyboard. This key automatically becomes the root key. Choose between major and minor and add diminished or augmented additional notes. The third can be omitted. Also you can invert the chord (the root note is no longer lowest). All functions can be randomized to get weird chord progressions.
Check out the video tutorial:
This way for heaps more Max for Live devices & tips.