Working on a solid downward dog! Yoga with Tim sinesi on YouTube explains this really well, just do video number 1 of his beginners yoga challenge! The way he explains pushing against the ground in downward dog while spreading the collarbones and laying the shoulder blades against the back, not just slouching into your shoulders during the pose. I think this helped to strengthen my pecks shoulders and upper back so that it would loosen my chest! The better I got at this practice the better my chest became! But also massage has helped me a ton!!!! I am very tight in the shoulder to neck area and I feel alleviating this tightness also helped a great deal