You can have a bad caliper or pad isn't positioned properly. If the old pads were worn badly, groves in the roters can make it lock up. They should have been mic'ed and or resurfaced... sometimes buying new rotors is cheaper than paying for the resurfacing. Buying cheap $20 pads will tear up in the deep groves of rotors fast.
CHECK out your calipers
Sounds like the caliper slides may be seized.
This is a question forum about the business O'Reilly Auto Parts. You are unlikely to get an answer to your brake pad related question, in this forum.
Your calipers may be stuck from opening all the way. Is one or both rotors very hot? It's better to ask a question like this on the Scotty Kilmer Google Plus page.q
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