OOOF that sucks.
Before I weigh in, I just want to make sure: were you seen by a physician following your motor vehicle crash, to make sure you didn't have any fractures underlying your pain?
As for my opinion about chiropractic, I'm of course going to be a little biased (as a student physical therapist) but here's my take on it: chiropractic can give you short-term relief but then you may keep having to go back.
The small muscles around your spine do not get exercised or strengthened with chiropractic, which is often what you need following an injury or with back pain in general. Physical therapy works toward restoring those muscles to functioning the way they are meant to: contracting when they are supposed to, and relaxing when they are supposed to. When those muscles are nice and strong, they support your spine's natural curvature in all different positions and motions, but when you have an injury, those muscles sort of go into shock, and don't do their job properly, and moving can cause you to feel pain. That's why it's so important to get them working well again! The PT will teach you and assist you with exercises that start out very simple, usually lying down, so that you learn how it feels to use those little muscles and then over time will progress to things like bridging and hands and knees and then standing and moving quickly. They will probably also do some stretching and work with the muscles and spine with their hands to help relieve pain and tension.
Then, once you're back to moving without such extreme pain, the idea is that as long as you keep moving your back and exercising it in healthy ways, you hopefully don't need to go back to PT.
So in terms of long-term, physical therapy has a lot to offer that you may not get with chiropractic.
Chiropractor vs. Physical Therapy: Effective for the Back | LIVESTRONG.COM
edit: ah sorry, I just saw that I was tagged, and posted before reading through the whole thread. I'm actually super surprised that the physician did not mention PT as one of the options for you. It's also non-invasive and can have as good (or often better) long-term results compared to surgery, without all the complications and risks.
I would ask your physician about a good physical therapist that s/he recommends for back pain.
I also agree with what others have said about the spine curvatures not necessarily being a bad thing or the cause of your problems. Reduced spine curvature is
associated with back pain, but not everyone with a "flat" spine necessarily has back pain. You may be able to get some of the curves back with PT, as your pain subsides (eg your body might be holding itself in that rigid position to "protect" itself from further pain), or you may reduce your pain and keep the straighter spine. But really it is the pain that is bothering you, right?
