I have the same exact problem in the same area of the back and went to see a specialist yesterday. He ordered physical therapy for 6 weeks and what he felt was the least toxic pain medication for the liver. It is Percoset 10mg /325. The 325 is the acetaminophen value. He said this is better than the former 7.5mg Oxycodone.
Now... as for the cortisone injection. My Gastro strongly suggests NOT having those type of injections. I was offered that yesterday and refused it. There is a milder version of the injection, but ask your Gastroenterologist.
I've had a Laminectomy: http://www.mayoclinic.com/health/laminectomy/MY00674/ (surgery of L 4-5), which involves the removal of half of the disk to allow the spinal cord to expand to its normal size, which will get rid of the pain. The surgery is not major and lasts 45-60 minutes. Before you make any decisions, always ask your Gastro.. Best of luck...
Magnum
Thanks for your feedback it was helpful. Unfortunatly I was in a trial and don't have a Gastro so I am not sure what I am going to do.