My MRSA tends to grow in my right lung, and my pseudo in my left. There is a little bit of crossover, but when I feel a mucus plug shift from the right, the MRSA is always an outrageously high number, and the same for my left side. I've thankfully never grown cepacia, knock on wood.
I noticed that MRSA has a very specific cough, though. Personally, it sounds more asthmatic, with a coughing fit of shallow coughs that is rarely ever productive. It also tends to trigger my gag reflex. When I talked about this with my doctor, she noted that several other patients of hers have described the MRSA cough the same way. Not sure if this help you or not, but it's an interesting thing to note.
I'd call your doctor and ask for their opinion.