I'm always coughing up phlegm, no allergies, started before I started smoking a year ago, recently quit and its still there. How can I get rid of it?

Need diagnosis... Possible etiologies for your symptoms include bronchospasm from any cause, post-nasal drip, gerd or even a combination of these factors. Each of these has a different treatment so see your doctor for diagnosis and treatment. Avoid smoking to decrease airway inflammation which could worsen these symptoms! congrats on quitting!
Phlegm. Increase in phlegm production occurs secondary to inflammation( from smoking or viruses, bacterias, other irritants, allergies or bronchectasias) coming from sinuses or airway. Very difficult to treat some drs will give antibiotics and steroids ( cortisone).