Best excercise is sat down bent over dumbell flys ( perfect form is key, use a very low weight to start with and work your way up with PERFECT form )
The below excercises don't directly hit it but I feel really help shape that whole region
lat pulldowns with wide overhand grip
narrow underhand grip pulldowns.
T bar rows
Rear delts are one of the most important muscles in my mind, get it wrong and your side profile looks completly distorted.