OK, firstly: Welcome, friend
Re: Cigarette AddictionAs a preface, I cannot really speak about conventional addiction though I do consider myself to have been addicted to video games and junk food for most of my life up until about 4 years ago. I was never addicted to any drug, thankfully - I guess I am just not an addictive personality in that regard.
That said, I do a lot of reading on compliance and persuasion because its a main part of my job. One thing that Beretta did not mention directly is to make your commitment to quitting public. Public commitments go much further in driving behavior modification. To give you an example, one technique I have heard is that you can make a business card (get a pack of 100 for 12 bucks) that just has your name on it with the statement "I am never going to smoke a cigarette again" and give that to everyone that you want to respect you - family, friends, etc. Think about how much they would be disappointed if you went back on your word - they will always have the card that says you were going to do it and it would be horrible if that weren't true.
Kind of just a side note from some of the reading I have done.
Re: Years of AbuseWhile you can never really go back in time and change things you have done, you can still be a beast and live with yourself. To give you some hope, I had 4 shoulder surgeries for chronic dislocations and I grew up with osgood schlatters and am highly prone to patellar tendinitis. I used to not even be able to reach into the back of my fridge without my shoulders popping out of their sockets....so how could I even think about being a traceur?
I attribute my shoulder stability to a few things. Surgery certainly did help but that was not nearly as critical as the amount of strength work I do. Overhead lifts used to scare the shit out of me because I would fear a dislocation where the weight would come crashing down on my head. Now I can do full range-of-motion handstand pushups, a 1xBW Overhead press with a barbell and tons of gymnastics work on bars and rings that involves some pretty brutal forces on my shoulder joint. The point is, get started on an exercise program, particularly focusing on strength, and you will see a lot of improvement in the "shakiness" of your body.
Having a list of goals here would help us to help you get started. Exercise also helps on kicking addictions, btw.
If you want to be strong, let us know the movements in which you would like to be strongest. If you want to be big, let us know how much weight you would like to accumulate. If you want to go slow, let us know. If you want to go balls out, we can arrange a program for that, too. Let us know what works best for you based on the kind of person you know yourself to be!