This spinal rotation exercise and stretch will wake up the muscles in your obliques and upper back.

Start on all fours with your hands below your shoulders and your knees below your hips. Place your right hand behind your head and then rotate your torso to point your right elbow toward the ceiling, as far as is comfortable. Pause, then slowly lower back down, pointing your right elbow to the floor.
Do 5 reps, then repeat on the other side.

Cautionary note: If you have osteoporosis, twisting and bending moves may not be right for you. Talk to your doctor about safe exercise.