i have a shoulder injury and need tips how to continue losing weight and exercising without pain.

I am very disappointed. My highest weight was 240lbs. I quit soda when I saw that number and in a week I was down to 234lbs which is when I started to track my weight loss. I was down to 217lbs. I was in a car accident and have a rotator cuff injury. It didn't fully set in until 6 months after the accident, all the time up until then I had been losing weight. I couldn't lift more then 5lbs or my shoulder would lock. My doctor said it sounded like frozen shoulder. It took a long time to get physical therapy, I was a passenger so I had to go through the drivers insurance who was very difficult and took almost 6 months to get treatment! I had spasms everyday in my shoulder going up my neck, I practically stopped using my left arm. I had. Immense pain, even drinking from a glass in my hand was painful. It was too hard to put my hair in a ponytail, sometimes I couldn't take off my shirt my shoulder was that bad. To this day It still hurts to lay on my arm and use my hand for long periods of time. I also have depression so this made me miserable and I really wanted to die. I over used my right arm and then that arm got bad by the time I got physical therapy. I have a moderate to severe shoulder injury and I go to physical therapy 3 times a week. It hurts to run, the swinging motion kills, it feels like a knife pushed into the centre of my rotator cuff. It hurts to do sit-ups, and to extend my arm above my head. I tried to do water aerobics and that hurt. My arm is a lot better than it was before, but my healing feels stuck. I am still in pain everyday, I only get muscle spasms if I'm stressed or lift to much or over use my arm. It is very difficult to live my life, and work in pain constantly. I couldn't exercise due to the pain, couldn't even walk my huskies. I stopped eating healthy and it's been about a year to a year and a half since I've been exercising and eating healthy. This last few months I've been really drinking the coca-cola and as of August I stopped drinking water every day at work and have been drinking any soda. Im now weighting in at 232.6 lbs and I am 5 foot 7 (170cm exactly). I am overweight and I need to get healthy and I am very disappointed as it took a year to get off that 40lbs. I would really like to get back into eating healthier, giving up the soda and the sweets ( really have a sweet tooth lately) and finding any exercise I can do. If anyone with a shoulder injury could give me advice on exercises I could do that would be greatly appreciated. And if anyone could give me some tips to get off the soda and sweets and to actually eat and get healthy it would be fantastic. I really wish my injury would heal, I fear I will be in pain forever. I just turned 21 last week and I need to get in shape and get healthy. Thanks In advance for all your tips, comments, and advice. It's been a rough couple of years and I'm finding it so hard.