Sizes run SMALL. I typically wear a Small or Extra Small in Shirt sizes. I wear a Medium in these tops. 

Order 1 size up than what you think you would need. Shirts are stretchy and form fitting.

I am 5'9 size 32DD 133lbs- size Medium

@Sarah_bowmar wears a Large. (Due to a wider back, larger breasts and being a boss lady beast.)