Either your Dr. is an idiot, or you misunderstood what he said. I have a feeling it was a communication thing, and the Dr. is not an idiot and you simply misunderstood him.
Developed chest muscles do not cause the back to be proportionately weaker....BUT a well-developed chest accompanied by a weak, underdeveloped back is a sign that a trainee works their chest excessively at the expense of proper back training, and thus develops an inblance. Most people seen at most commercial gyms have this issue due to America's obsession and fascination with the bench press to the point where it causes neglect of the rest of the body.
You should set a goal for yourself. Your STRICT barbell row performed correctly should be about equal to your bench press numbers. Working towards this goal should take care of your problem.