If you want to work on your shoulder mobility and your core at the same time give this a try.
Straight Arm Supine Grip Band Pulls with Band 2 sec pull, 1 sec hold, 2 sec release
1. Stand upright, with a light resistance band in your hands. Lift your arms up in front of you at shoulder height, arms shoulder distance apart and palms up towards the ceiling.
2. From here, pull the band apart and bring your arms to either side of your body over a 2 second count. Hold 1 second, release to start position over a 2 second count