hsbb05
I've just found this thread, so sorry for the back problems your son has had. Hopefully he'll return to playing again soon. Please post what you learn at the ortho today.
A few years ago a friend's son had a bad ankle sprain after stepping in a hole while fielding a ball. The ankle eventually healed but he then started having problems with his legs & lower back. To make a long story short, they went to an orthopedic specialist and it turned out that his hip was jammed upwards and out of position, causing the lower back & leg problems. None of us had ever heard of anything like that, and it may have gone back to when he stepped in that hole. A few weeks of PT fixed it. Nothing like what your son has experienced with his back, but like with aerobicv son, it's worth keeping in mind that hip joint issues can present as, and cause, other problems.