The first and foremost you should do is preparing a diet chart. This is "THE" most important factor before you start your physical activity. Calculate BMI and depending on your age, weight you have to plan your diet. Avoid fried food, junk food, fast food, chocolates, desserts, ice creams, sweets, red meat and sodas completely from your diet. Eat healthy and plan a cardio activity initially to lose around 300 calories per day and depending on the amount of weight loss you want you can go till 500 calories per day. With cardio there is no problem to your back: running with proper running shoes and on good surfaces, jogging, swimming etc.
you can do deadlifts, however, if your back is in pain, they might not be the best idea. i think you shouldnt do heavy work, with a painful back is my opinion
Thank you very much for the quick and informative reply! I knew that lowering my weight and achieving a normal BMI would help with the back pain, just wasn't sure how to start. Thanks again!
You need to start with simple cardio initially. You must start following proper ergonomics. Wear proper footwear, sit and sleep on proper chairs and bed and also follow a perfect posture while you work, sit and sleep. Then you can start bending and stretching and do not continue if you experience pain. Weight control and achieving normal BMI in most of the cases reduces back pain completely. If you have chronic pain it is better for you to follow up with an orthopedician before you start any routine physical activity.