I would not really read too much into where you are pulling the bar into exactly (sternum or belly). Just be consistent with whatever way you choose to do it. I like to do them where my torso is almost parallel to the floor and I pull the bar to the bottom of my rib cage, maybe half way between my nipples and belly button. However, not everyone can do this and it may not be the most advantageous for you or the next guy.
Take some video of yourself and see what it looks like. A lot of folks lack solid posterior strength and the barbell row, when done correctly, really works the hamstrings and low back in order to keep a good position. So, if in the event you are still working to develop these muscles, then the BB row can obviously be a challenging exercise to master. I would say keep working it and just try to exercise excellent form while keeping a solid position.
Try not to force weight on the bar with the ambition to progress, either you can do good solid reps with the weight, or you can't. It is definitely better to put a lighter weight on the bar with rows and really focus on scapular retraction and really pulling with your back. Just keep training it. Over time, like your other lifts, you will develop better motor skills and strength with the exercise.