Best Back Pain Exercises

My tailbone/lower back area has been killing me, and I was just wondering if anyone knew of any exercises or stretches that would help alleviate the pain? Thanks!
I had physical therapy for 3 months of my life when I was in a car accident, and at this point and time while it would be nice to do again it would be too costly for me to afford.

Are there any websites or exercises that help relieve lower back pain. My back always feels like its going to snap off or something when i try making fast movements. its been like that for years since an accident, but i dont have medical so i cant ask a doctor.

Any advice would be greatly appreciated. Is yoga any good.