I've been around secondhand smoke my entire life. i'm 23. what should i do to examine how much damage has been done to my lungs?

Pulmonary function..: You can have a test called a pulmonary function test. This test will show whether there is airways obstruction and, if present, whether the obstruction is reversible with bronchodilator medication (like asthma) or whether it is not reversible (like copd). The test will also reveal restrictive disease, if present. Your family doctor can order the test or you can see a lung doctor.