Welcome. I will try my best to help you and in order to do that, I need you to describe as best you can because I only know as much about your problem as you have told me in your post, so my answer will be based on what you have posted. Please feel free to reply as needed.
Did you have the park brake appied?
OK., check the brakes, both the pads and the park brake shoes.
Take the 8 bolts out of the axle and see if the wheel will turn. This will drop some gear oil, but it will tell us if the issue is in the hub/bearing or the diff.
Chevy Technician
GM Grand Master Technician 2007. 9 years Automotive experience, 7 years with GM. Just Answer Mentor