my son is in pain after back surgery which involved screwing bolts and screws to his 3rd and 4th vertebrae to give stability to a bulging disc along with grafting on bones he has no nerve damage but his both legs have pressure build from hips down that is his legs are always tight and hard and he cant walk long distances and stand for long before he needs to sit down his surgeon has no idea or is not giving anything away do you think his body has rejected the metal of bolts and screws or another opinion would be appreciated .