No, it's not true. Quitting smoking is one of the very best things you can do for your health. It's expected that you may experience various symptoms when you first stop smoking because you are going through nicotine withdrawal and the body needs time to adjust. This should settle down after about a month though.  Sometimes, smoking masks an underlying condition that people become more aware of when they quit. You should discuss quitting smoking with your doctor, and what tools may be helpful for you. You should also report any new symptoms to your doctor.