Have Thoracic Back Pain, MRI Shows Spinal Twist. Any Ideas?

I have thoracic back pain and have for the last 2 years since delivering my 2nd child. MRI only showed a slight twist in my spine and nothing else. I was told it could be the beginnings of arthritis , but more or less the doctor didn t see anything. I have had myofacia (sp?) injections that last a couple of weeks and nothing more. I did have a chiropractor tell me that I had one leg longer than the other, but a very minimal difference. My job requires lots of heavy lifting and standing on my feet all day. Any ideas what else it could be? I feel like 2 years have been going by with me seeing my doctor and I am not getting answers to what it is because it isn t obvious.