Rattle near right front wheel

I hear an intermittent rattling noise which sounds like it is coming from the right side near the wheel. It sounds also like it could be something dragging. I hear it after I make a turn then it goes away. Husband looked under car found nothing, brought it to a mechanic who cleaned and adj. brakes and said that took care of it. Ha, not quite. Any idea what this noise could be?

 

I brought the car back to the mechanic who drove 50' with me before we heard the rattle. It was a small rock between something (I forgot the part name) and in front of the heat shield.