The only time I get that is if I go a very long time with no cardio (as in 3-4 months or more) or I am eating so often (something that truly becomes a job the bigger you get) that my diaphragm is lifted due to an increased overall food intake. It usually doesn't take long for my body to adjust however. For instance, I am currently about 260lbs.
The first time a couple of years ago that I hit 260, my lower back would sometimes hurt if I stood for too long. Now, 260 feels comfortable to me as I have been heavier than this and I am carrying less body fat than I was the first time I hit this weight. Forcing your body to accept greater weights isn't something your body always accepts easily. If your stomach is empty and you still feel out of breath, you need more cardio.