It can be frustrating to live with chronic pain, especially of the back. However, even though it sounds simplistic, in a way, your doctor has a point.
Studies have been done that evaluate how people with chronic lower back pain see and accept their pain. Those who accept their pain and move on do tend to have a better quality of life than those who accept it but then are resigned to it.
It may be helpful to speak with your doctor about ways that you can try to live with the pain and still go about and do things you really want to do. Activities may require some adjustment or accommodation for the pain, but if you are active, you may build up enough enjoyment in what you are doing to be able to pass the frustration that can develop with chronic pain.