if you suspect brake drag, drive along at a decent clip and apply the e-brake. this will most likely change the sound/feel of the problem.
i have lost a rear wheel bearing and i thought the rear of the car was gonna fall off. the way i test for that is to jack the rear end up and use jack stands and all that. be real secure. then start it up (dont knock it off the jack stands when you start it up), put it in 3rd or 4th and you will actually see the wheel hopping around. i doubt this is it though.
id just jack up the pass side and give it a once over. check all moving parts. noises, esp from rear end, are real hard to diagnose, as the sound diffuses.
good luck and congrats on the new ride.