I shoot a very vertical bow position like you do, Iowa. My advice would be to make sure you're getting to full draw with proper shoulder rotation. Check Terry's form clock image. Then, make sure you're not torquing the bow. The final steps would be paper tuning and bare shaft tuning your bow. You could be shooting left because of too stiff of spine. I am a gap shooter and sometimes I get left arrows too. If you have proper alignment and good form, that should correct most problems. When I struggle with left/ right arrows, sometimes it's form breakdowns. Other times and with a bow I haven't shot much, I could be the arrows. When I mess around with arrow shaft sizes and tip weights, that seems to help. Also make sure to check your brace height for your bow.