Jerking Noise From Back

[JB0]

I got my rear brake pads changed(post MOT) as they were worn out. However, there seems to be a new noise emanating from the back of the car. Weirdly, the noise usually starts first thing in morning, when I start engine and appears as though it's coming from the back. Also, when I sit in the drivers seat, it makes that same noise, before switching engine on.

I did tak car back to garage but it didn't mk that noise then. The mechanic advised that it's the nw brake pads grinding in or something.

Can someone please advise?

[JB0]

I just pressed down on the back of the car(left and right), and it made that noise...like metal clunking. ..I definitely think its something to do with breakpads.