I'd first pull your wheels off and have a look at the pads, rotors and calipers. Make sure there is nothing obvious. Take the pads out and see if you can squeeze in the pistons in the calipers.
Your brake hoses could be bad. When they go bad the swell on the inside and start to work similar to a check valve. You can apply the brakes, but the since they are swelled inside the fluid isn't allowed back when you release the brake, and keeps the brakes applied. This causes the brakes to drag which will heat up your pads, rotors, and calipers, which can cause them to seize up. Then when cooled down they work again.

__________________