Avoid trying to fully retract (pull the shoulders back and together) at the beginning of your rows. It will result in limited range of motion for the prime movers in the exercise.
When trying to train the upper back musculature, start by simply creating tension in the upper back to stabilize the shoulder blades. Then, once your elbows get past the mid-line of your torso, complete the movement with retraction while you continue to drive the elbows backwards.