How can i do a parkour roll with out messing up my shoulder?

practice summersaults first from a standing position before you do anything that could hurt you. roll from right shoulder to left hip so the ground takes the longest route on your back.

Get some training from an experience coach.

Make sure that your roll is traveling from your hand, along your curved arm, to your shoulder. It should be smooth. Don’t collapse from your hand straight to your shoulder.

Also visit americanparkour.com

It’s a great resource for both new and experience traceurs. Lots of good information, lots of helpful people. Happy training.