Lose weight. Excess load can stress the spine.
Maintain good sitting posture during work. Foot flat on the floor.
Protect your back from cold ACs during long exposures. Wear coat if possible or position your chair opposite the cold source.

Do the stretch (pain-reliever therapy):
-If alone, lie on a single-size bed, facing right side. Extend your left leg further forward. Then slowly turn your body to the left side letting the weight of your left leg to pull your back muscles until you hear a popping sound. A refreshing snap actually. Repeat facing the left side also.
-If with companion, snag your arms back-to-back and let your companion carry you by leaning forward. You will hear the same resfreshing popping sound.

Do other safe stretching routines you can imagine (like the cat does).