I Am Trying To Quit Smoking And Today Was The

I am trying to quit smoking and today was the last one, I no longer has ability to take a full inhale because decreasing in lung capacity I guess, but it has affected the posture of the spine and I can only imagine because it cant expand like it used too. Trying to get into shape again because of a fractured ankle but the more so done it feels as if i am going to have a heart attack. I am only 18 and only smoked for 2 years. How do the lungs get back to normal. Breathing feels pressure and covered in tar.