A quick way to increase mobility and flexibility in your spine is to stretch your abdominals, shoulders, and neck. One exercise to do this is the classic Seated Spinal Twist that also stretches your hips, glutes, and back.
Steps to do a Seated Spinal Twist:
Note: If you are a beginner and don't have the muscle flexibility yet, start by placing your hand on the outside of the opposite leg to begin the twist. As your body's mobility and ability to twist increases you can place your elbow and arm to the outside of the opposite leg.
Muscles You're Activating
Keep comfort in mind. A way to make this pose more comfortable is to keep both legs straight.
For an extra stretch, add in neck rotations during this pose by turning your head left and right before relaxing back to a neutral position.
You can do 5 to 10 reps on each side, give it a try!