You need to put anti squeal, It is a liquid rubber that is applied to the steel back of the pads, I prevents the vibration of the pads ( they all do it ) from being transmitted to the caliper. Back when they had real parts stores with real parts men behind the counter they would not let you out of the store without the anti squeal and synthetic brake lube grease for the pins. Some pads have the anti squeal factory applied, some don't. You can get the anti squeal and lube at auto zone, Checker... or pay more at napa.
Don't forget to break the glaze ( called re-surfacing when done mechanicaly ) on the rotors while the calipers are off. It does 2 things, one: it will allow the pads to wear on faster, two: it will reduce or eliminate potenial squeal. 120 grit sand paper or emery cloth works well. The sanding should be done perpendicular to rotation or so the finish is non directional.
A brake reline is more than just throwing in new pads. If you do it right. There are knukel busters and there are mechanics