Rainjack,
I can’t tell you anything about ART, but I would defintely tell you not to give up hope. While I am not a doctor, it does not sound like you did permanent damage to your back when you squatted.
If you can, you should see a second doctor. I injured my lower back doing jerks once, and compounded it when a week later I did what I thought was “light” pressing but my back didn’t.
I was sent to a physical therapist who believed it was something structural (can’t remember the proper terms right now), he regularly did some massages, and would slide my back into position. It seemed like what he was doing was working. It gave some immediate relief, but after several weeks my back still was not better.
I was abroad, and when I returned home several months after the injury, I saw three more doctors, two of whom had sports backgrounds. The first two had various theories after looking at the x-rays. The third took a look, and said, your back is fine. He said I had strained it badly, but now should be good to go. So the next day I started squatting, doing pulls, etc. again with no problems.
What I learned is this: not all doctors are good at diagnosing sports injuries, and even many sports doctors poorly understand weightlifting/weight-training and the strains and stresses it does and does not put on an athlete. Perhaps this is because the majority of patients who have injured their backs, knees, etc. are sedentary people in terrible shape, and so if Jo Shmoe throws out his back doing some light snow shoveling or bending over to pick up a 35 lb box, and the next patient is talking about squatting 400+ lbs, the doctor is horrified and in disbelief.
The other thing is to be patient. Some injuries take a long time to heal, but they heal nonetheless. Finding a doctor and/or therapist with experience with athletic experience can make a world of difference in getting an accurate diagnosis and an effective rehabilitation program (also very important, I have learned with experience).