How is your bed? I remember having back pain as a kid after my parents got me a new mattress. It was okay for a while. Maybe a couple of years. But then the pain began. Actually I knew it was the bed because the pain would be worse when I got up in the morning and slowly by the end of the day it would go away. New mattress solved the problem. You might also try a memory foam mattress topper.
I'm not saying there is no other problem. There may well be. As for the chiropractor, my daughter and I have gone. Worked wonders for her. And although I was helped after the initial two visits, after that it didn't seem to help. Depending on what is wrong, it could take several visits. That being said...
I would start with the MD first. I say this because my daughter recently got healed from a near stress fracture. I had taken her to the MD for this but they dismissed it as a strain. I was going to take her to the Chiropractor but something stopped me. And I shudder to think of what might have happened had I done that.