d be contacting my doctor, could also be indicator of the beginning of a blood clot,(the popliteal artery is found behind the
knee, a common place for clots to form) the
knee and calf area especially since you've stated that you experience this both at rest as well as with exercise.
I personally would either a) contact my PCP or b) contact the surgeon who preformed the surgery for an appointment or c) go to the ER's express care service with the complaint.