Congratulations on your decision to quit AND your negative test results. I quit 6 years ago after smoking for about 40 years. I too had an X-ray come back showing problems. In my case it was emphysema. In addition I have chronic bronchitis so I now get to list COPD as one of my afflictions on medical questionnaies. All from smoking. Starting was the worst decision I ever made.
When I decidied to quit I used Chantix. I smoked the first week that I used it and then after that I quit. And now, six years later, I still want one from time to time, but the urge is fleeting. And today, even with the COPD, I can do a 5 mile walk, with some pretty good hills along the way, in less than an hour and a half. My brochitis hasn't flared up since I quit smoking and I rarely get a cold. Today, at 62, I feel healthier than I did at 40.
I say all that to say this. You're going to have some tough times ahead. Nicotine is one of the hardest drugs to get off of. Just stick with it. When the urge hits you, do something, anything, to take your mind off of it. The urge won't last more than a few minutes. After about a week or so, you'll be over the physical addiction. Then the habit itself has to be dealt with and this is the really hard part of quitting. Wanting to smoke when your bored, after a meal, while your reading, watching TV, etc. You get the picture. But, like I said, the urge only lasts a few minutes. And before you know it, you'll start feeling a lot beter, you'll definitely smell better 
, and you'll have a heckuva lot more money!
Good luck and keep us updated on yur progress!
Cary