Do you know if you did anthing to cause this pain flare up? Did you lift something and have immediate pain?
Also, how long has this been going on? If it has been going on for a long time, definitely make an appt to see your doctor.
I would say that you should give it 6 weeks if the pain is not severe and try no lifting, bending or twisting and if you can tolerate them try an anti-inflammatory to help reduce the swelling. Sometimes we simply need to allow our bodies TIME to heal. However, if the pain is severe, forget my advice and see your dr right away. No one should have to suffer.
If after you have babied you back it is not better then I would definitely return back to your dr, explain to him how your pain is really not getting any better and request an MRI.
If they refuse to order an MRI, I would seek another doctor for their opinion.
Also remeraber that we are simply other spinneys and not medical doctors so your best course of action is to seek the advice of your doctor and listen to his recommendations. However, if you are not satisfied with their advice I recommend seeking a second opinion.
Good luck and please keep us posted. We care and pray that you will soon be feeling much better.