I've been in a car accident too - they SUCK.
Anyway, everything everyone said about stretching is TRUE. And chiropractors can help. I personally had better luck with massage therapy.
I understand about the $ thing, but if you go to a Dr. first (chiropractors count), then they can write you a prescription for massage therapy - you just have to go to someone who is licensed - i.e. has an L.M.T. certification. My insurance will cover it as long as I have a prescription and I go to an LMT.
Also, look in the phone book and see if there are any massage training schools near you. To get an LMT, you have to do lots and lots of massages. They need people! So you can get a massage there for a lot cheaper. (usually at least 1/2 price).
Also, NUMBER ONE ADVICE...
Pay attention to how you carry yourself. How you stand, sit, lay down, etc.
You should NEVER sleep on your stomach. Get an foam "egg crate" pad for your bed - they are CHEAP and really help. Sleep on your back or on your side with a pillow between your knees. That way your spine is in better alignment.
Stand straight, like your mama told you to.

Picture a string that connects at the top of your head and runs down through your neck and spine. The string "pulls" up on you. Your back should curve outward below the shoulders then curve inward right above your butt. If you feel yourself slouching, lift your rib cage up and keep your shoulders and arms loose - you will naturally fall into a better position.
And I know we ladies love 'em, but ditch the high heels for awhile. They throw everything out of wack.
When you sit, especially for long periods, make sure to keep that curve in your lower back. Don't hunch over. And don't work where you must sit with your back twisted one way or the other for a long period - move your work so it's right in front of you.
Finally, take yoga if you can. Works wonders for the posture, stability, and strength of all the important muscle groups that can alleviate your pain. Plus all that nice stress-relief too.
Good luck and I hope you feel better!