>>76387685Well, losing weight is done with fork put downs till failure and increasing daily activity, but you already know that.
Now your arm: you have to start with ridiculously low weight, I mean, it should almost feel silly, and basically work on muscular endurance: 20-30 reps for 2-3 sets.
Since your arm is screwed it's common to spare it from daily activities, which will in time constrain your shoulder movement and atrophy the muscles surrounding it. Don't. A little pain is fine, it's a warning to be careful, not a full blown back off. Intense and worsening pain means stop. Prioritise shoulder mobility movements.
Currently you are below normal and have to work yourself up to average, it will take time.
Trust in the process, believe in yourself and your ability to heal, and it WILL get better.