Because you have a history of MAC and now have what sounds like a chest infection of some sort, you should be seeing the doctor as soon as possible.
The doctor will then listen to your chest and prescribe an antibiotic and possibly may also prescribe you with an inhaler to help you breathe.
Please see your GP as soon as possible.
I went to my GP today and he did a chest xray. My right lung showed a white area. I had an xray done in June of 2012 and the white area is much larger than it was then. I haven't heard anything yet. My GP put me on azithromycin for 3 days. I asked if it could be the mac reoccuring and he did not know.
I am glad that you went to the GP and are being sorted out. At the same time sorry to hear that the white mark has got much larger.
I did not know anything about MAC so read up about it on the web. According to what I have read, you should be on medication all the time. This is a condition that does not go away and people with a lowered immune systems and HIV postives are prone to getting this. It is not contageous to others if it is MAC.
May sure that after 3 days on the azithomycin you go back to the doctor so that he can listen to your chest again to make sure that the medication has worked. If not, he will need to prescribe either more or a different antibiotic. It may be worth asking the doctor if he can send some of your phlegm (if you can cough any up) to be analysed so that you are prescribed with an antibiotic that will zap the bugs that are causing your problem.
If you smoke, then stop, and keep away from any smoke filled rooms and keep warm. Don't know what the weather is like where you are, but it is very cold here in the UK. So if it is cold where you are, wrap a scarf around your mouth so that you do not breath in the cold air.
Alterntively, if he doesn't know, he should be referring you to a lung specialist.
Hope you get on alright.
Best wishes.