I had my mechanic fix my brakes but they still make noise, he says to run

by fix, i am guessing change? did u have rotors and pads changed? were the calipers inspected thoroughly? is the noise continuous or only when applied? what color was the brake fluid? if noise is continuous then possible calipers are not releasing as they should. ask the tech. that did the job if calipers were difficult to open as this is a sign the calipers themselves may be faulty. ask him if the old pads showed excessively uneven wear. same reason. in either case the calipers need servicing(cleaning; caliper pistons will take on sludge build up causing malfunction) or out right replacement. in some cases i have seen cheap rotors with ceramic pads(not recommended). the pads are a sacrifiscial metal and designed to wear. ceramic pads are so hard that they will wear out cheap rotors prematurely(even cause them to sing).