If your disc brakes are rubbing they are probably making a little noise. Spin the wheel while holding your ear near to the caliper to see if you can hear anything. One of the discs on my new Catrike was making a little noise intermittantly. I was able to tighten one of the six disc mounting screws about 1/8 turn and that fixed it.

The most likely cause for a wheel not spinning for very long is too much bearing preload. That's a pretty precise adjustment between too tight and too loose.