Discomfort in the chest

I have been using my machine for just about 5 weeks now. I had the muscle pain in my chest starting out and it seemed to go away. Recently I have that same feeling back. I understand that a lot of that is from the chest expanding more than it has in a long time but how long does it usually take for everything to start to feel normal?

Everyone's different. But why wait around to find out if anything else might coincidentally be going on - see your doctor.