Is there any good way to get rid of phlegm?

I've had a lot my whole life in my lungs, and it's caused many cases of pneumonia, not to mention the fact that I'm considering going for a flute scholarship and it's highly diminishing my ability to play. I also love singing and voice acting but it's taking away from my ability to do those as well. It's also very embaring at school. I've tried many things, and does anyone have any tips of their own? NOT something to do with medicine/puffers/inhalers please, my body doesn't react well to medicine.