Go back and nag your doctor for a diagnosis. Did he/she not say what the problem may be when you went before?
I wouldn't like to say exercise again if that was going to, in the long term, make the problem worse. Similarly, I wouldn't like to say rest it if that was going to, in the long term, heal it wrong.
I have found doctors take the least invasive course of action first. If you don't go back and say it hasn't worked, they will assume it has, you are all mended, and don't need any further intervention.