Were you able to see a doctor? Some areas/cities have clinics that take people on a sliding fee scale. If you have seen a doctor - were they able to determine what is bothering you? Has it gotten any better??
Also--if this upper back pain is the result of an auto accident, then normally the insurance of the person who hit you should be paying for any resulting doctor's bills. I don't know about your state, but in my state drivers are required to carry at least liability. Check and see, if your back is still hurting.
If you absolutely cannot see a doctor, there are stretches and such that you can do. Do a search for spine health and exercises. There are some competent resources available on the internet.
I went to physical therapy for nearly two years for a myriad of back problems. It helps, but for me, my problems are beyond physical therapy.
Have you tried biking(spin classes even)? Perhaps swimming? Most universities have both available. Both are no impact activities and pretty back friendly.
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