Anyone tell me why my brakes a squeeling?

Just changed them about a a month ago and it seems it only does it When they are warmed up. The calipers have the wedges to hold them in place, not the bolts and the pads do have the clips on the backs to hold it in place. Just the one side does it and it drives me nuts. I'm thinking maybe change the caliper wedges? I dunno. Any knowledge?