1999 camry brakes seizing up

Brakes seizing up . My 1999 camry started shuddering and eventually heated up the rotors and warped them. I took the car to 2 different mechanics who said there was nothing wrong with my calipers. I changed the rotors and pads and the car worked perfect for a month. I parked it for a week and now I cant move it. The last time I drove it I could smell the distinct smell of brake friction. Is it possable for 2 calipers to go at the same time. I don't get any pulling to one side or the other. they just lock on until they seize up. Any suggestions