Hitting left a few inches can be caused by 1001 things, so I wouldn't worry about it at this stage of the game.
What you should do is try to develop good allignment and form. Check out Terry's clock, and have someone compare your allignment with that, or check out your own in the mirror. Hitting your arm guard can be caused by not coming to full draw with good back tension. Make sure your drawing forearm is in good allignment with your arrow at full draw. Or, you may be rotating your grip too much into the bow. With a recurve, the pressure should be toward the thumb side of the vee between your thumb and forefinger. Both of these things are basic to good shooting.
An optional thing that can help is to keep a slight bend in your bow arm. Some of us feel that a slight bend improves our shooting, some don't, so try it both ways and see what you like best.