If you've not been using your left hand much, then it's kind of tough at first but the more you use your left hand, the easier it will get for you. Do you practice and use tri-tones? I would suggest that you practice those tri-tones often, run up and down the board with them until it gets easier for you. If you've got the tritones down, then practice playing the triads (3 note chords) in your left hand and the single notes in your right hand. Whatever you had to put your left hand through to get it to become obedient is the same that you must do for the left hand. Practice, Practice, and more practice. God bless you and I wish you all the best.