Add your favorite music to your workout. It has been proven that people who listen to music while working out go faster than those that aren't listening to music. Studies have also shown that people who listen to music while exercising perceive their workouts as being easier to complete.
A good way to exercise your back muscles is to do pull ups. By using your own body weight, pull ups provide resistance equal to your own weight. Simply find a pull up bar, and pull your chin over the bar. For those who have never done pull ups or have had limited experience with them, it may be hard for the first few times, so try using a chair to aid you.
See a physician before starting a new exercise plan, especially if you aren't used to exercising. Discuss your general health and any concerns you have about starting to exercise. If you have unknown health problems you may do inappropriate exercises, or you may overdo it and cause injuries. As your fitness level increases you can do more intense and long lasting workouts.