As someone who spends a large part of day at a desk working on a computer I am all too familiar with shoulder tension. Below are a few stretches I try to incorporate to help combat shoulder tension.
Upper Trapezius Stretch - Start standing or sitting tall, place one hand on your lower back so your forehand is touching your lower back. Place the other hand on the opposite side of your head. Pull your head toward your shoulder. Hold for 30 seconds. Repeat on opposite side.
Thoracic Rotation - Start on all fours with your hands stacked under your shoulders and your knees under your hips. Place your left hand on the back of your head so the elbow points out to the left. Slowly rotate your head and shoulder toward your right hand on the floor. Then reverse the motion to bring your head and shoulder toward the ceiling. Continue the rotational pattern for 30 seconds. Repeat on opposite site.
Chest opener - Stand facing the corner of a room with your feet in a staggered stance (one foot in front of the other) with your arms raised and elbows bent at about shoulder height. Slowly lean forward pressing each palm into the wall as you bring your chest closer to the wall. Hold for 30 seconds. Repeat changing which leg is in front for your staggered stance.
Child's Pose - Kneel on the floor with your knees wider than hip-width apart and your toes together behind you. Sit back on your heels and fold forward. Extend your arms in front of you and rest your forehead on the floor. Gently press your chest and shoulders toward the ground. Hold for at least 30 seconds.
T-Spine Windmill - Lie on your right side with your knees stacked and bent at 90 degrees and your hips bent at 90 degrees. Extend your arms to the right and stack your arms and hands together on the floor. Slowly open up your upper body by bringing your left arm up and over to your left side, trying to get the left arm to the floor without moving your hips from off the ground. Slowly reverse the movement to bring the left arm back to right side stacking it back on top of the right side. Continue the pattern for 30 seconds. Repeat on opposite sides.