Whether the braces are painful or not depends on how well you take care of the new set of braces. You will feel pain during the braces process due to the force exerted by the orthodontic appliance to apply pressure on the teeth to push them into the correct position on the arch. Usually the pain state of the braces is only from the first 3-5 days after attachment and the first days when the elastic or coil springs to move the teeth.
The pain goes down and you will only feel discomfortable because you are not used to having braces on your teeth. After 5-10 days you will run out of that feeling and get used to living with that set of braces. The pain level will also be gradually reduced when you know how to clean your teeth as well as eat properly as prescribed by your treating doctor.