Is my chest pain and brown mucus from quitting smoking or pneumonia?

About a month ago I was diagnosed with bronchitis and slight pneumonia. My doctor and the ER doctor both gave me medicines and an inhaler. I quit smoking and feel better but I am still having breathing problems and keep coughing up brown mucus or clear mucus with brown specks. Is the brown mucus due to my quitting of smoking or is there a chance I am still sick with pneumonia?