Is it ok to do back excercises or will it aggravate and cause more pain?

[Denraymon]

I fell off a roof (45 feet high) 17 years ago. I landed on a wrought Iron gate on my lower left side back. I was in chronic pain still after 3 years (and still now). ICU reported bilateral traumatic haemopneumothorax. Cardiothoracic team decided that surgery was not an option to repair the ribs. Consultant report reads- Left sided multiple rib fractures (8 seen on x-ray) and loss of volume in the left hemithorax. The diaphragm had lost its contour completely and there was the possibility that the left phrenic nerve has been damaged. There was also chest cage deformity as a result which will prevent the expansion of the left lung to its maximum. Dr. Raashed felt that nothing more could be done.