Hello I am 18 years old and I do smoke, what does it mean when I have phlegm in my throat, a tight chest, and I am wheezing. What should I do to help?

Infection or asthma. The first thing it means is that you should stop smoking. Your symptoms sound as if your lungs are in trouble possibly from asthma possibly from an infection and the smoking will only make things worse. You need to find a doctor and have him or her listen to your lungs because if you do have asthma and you leave it untreated it can be very serious. Once again, you should never smoke again.
YOU NEED TO QUIT. Smoking. Your airways are kindly asking you to quit. Listen please. They may not be as kind next time and your symptoms may worsen quickly.