Sit ups and crunches. Swimming will help as well. Although it may be painful at first, these are great exercises to do to help strengthen your back so you won't have as much pain to start with.

Try to eat less processed carbs and more green vegetables, salad, fruits, etc..  If you are having back problems, the best type of cardio for you will be walking.  Be sure that you have a good pair of sneakers and start walking.  The only way to effectivly loose inches around your waist is by excercise and diet.  You can not spot reduce fat, meaning you that you can not pick a paticular area of the body and reduce the fat in that area only.  check out any of the mens health or fitness sites on the internet for more information about loosing inches, reducing your fat, proper diet and excercise.  Good luck and best of health to you.

Very carefully and very slowly. You can do situps with a pillow under the small of your back.

As a health practioner I dont think that will do any thing major in back pain.