Sdog2012

I went to valvoline the other day and a little while after i left, something under my car started rattling, it seems to be coming from the back and it rattles and shakes the driver side of the car while i drive in a straight line, gets more intense as i speed up. this doesnt happen while im making turns left or right, only while im moving straight.. i dont know if its something the hacks at valvoline did becasue my car does have 165k miles on it, anything can happen to it!