Seems that the noise stops when you are pedaling. That suggests to me the spoke protector is rubbing against the backside of the cog. When you are pedaling, the spoke protector & freewheel are turning at the smae speed together, so no rubbing. You could have a shop remove the freewheel and reseat the spoke protector, or replace it with a better fitting one. For general purpose riding, I would suggest keeping a properly set spoke protector.