2005 Chevy Venture Thumping Noise From Rear Passenger Wheel

The thumping noise is heard clearly at lower speeds. The thumping stops when I apply the brakes normally or with the emergency brake, but resumes when brakes are released. I have rotated the tires, the rear brake pads have 5K, the drum replaced with a new one. I rotated the tires and the thumping sound still the same from the rear passenger side. If I spin the drum by hand I feel a slight resistance at a certain point then it is free again. The same thing happenned with the old drum. The resistance is probably the brake shoe contacting. I back off the adjusters, but they self adjust to the same place. Thumping has become more consistent in the past few weeks.

Do I have a bad wheel bearing? How do I check the bearing?