Brake problem

You can jack up each front wheel one at a time, and spin it. It works even better if someone can apply a very light amount of brake pressure when you do it, and you can tell if you have a warped rotor. Also, just to be safe, double check your caliper bolts from where you re-installed it after the pads. 9 times out of 10, if it just started after new brakes, you may have a warped rotor. The store should take it back if I am correct. Good luck.