looking for support

I have been on and off this app due to some family issues that came up. I am back and determined to lose the 44 pounds I need to lose. I weighed more than I originally thought which was very discouraging, I live in Phoenix, and it's way too hot to go out and exercise so I do what I can. I also suffer with constant pain in my lower back due to ddd, which makes it harder. I really need some tips on calorie burning exercises that will be easy on my back.