Thankfully, the butchers at Market Meats came to my rescue.
He started off with a whole piece of skinless bones chicken breast, cut it in half, and trimmed the excess fat. He showed me that the side of the breast that was at the center of the chest was tough and hard to cut through (center in the photo). It is better to cut from the outside in.
He placed the chicken, rib side down, and pressed down firmly on the meat with all his fingers up He was not going to cut it from the middle (which I had been doing and causing holes in my chicken). Instead, he cut the chicken about ⅔ way up. cut from his right to left .
He left about ⅓ to ½ of an inch uncut and simply fold the chicken out. Then he placed a plastic sheet over the chicken and GENTLY pound it with his tenderizer a few times. (I had been doing this wrong too, because I was pounding the chicken with all my strength).