I have had back pain for 10 years since a bad car accident. Any chance it wil ever be better?

Not likely. The data is fairly consistent on back and neck pain after car accidents. If pain is chronic greater than 1 year it tends to remain problematic. Treatments can be useful if you get connected with a good spine specialist and get an accurate diagnosis.
Not unless...... You find out just what you have done. Can not be that bad - you are still around. You owe it to yourself to find out see aninterventional pain doctor with the highest qualifications (abipp or fipp).