I get at least double the milk out of my right breast compared to my left. How do I boost milk production of my left breast?

I have asked my lactation consultant and she said is normal. Sometimes one breast might be less responsive to the pump than another breast. It's normal. Just make sure baby latch on the side that got lesser milk in the next session.

Here is a great article that talks about what you can do: http://sg.theasianparent.com/causes-breastfeeding-women-milk-one-breast-can/

Latch baby more often or pump more often on your left.