Lunging Arm Circles is a great exercise that opens the shoulders and hips at the same time:
Lunge forward on left foot. Keep knee and ankle aligned. Right leg is stretched out long behind you, knee on floor. Actively pull left heel and right knee towards each other to square pelvis. Place right hand on floor or block and reach left arm forward, up and back for complete circles. Let focus follow hand. Do several rotations and then switch sides.