Here are a few helpful tips that you can apply:

Sitting at a desk for 8 hours a day is not safe as it can cause chronic pain and  lumbago. It is therefore important to optimize the ergonomics of your workstation. 

Posture et position correcte bureau, ergonomie et prévention du mal de dos

Some basic stretching exercises can help in reducing back pain and they are just  as important as creating an ergonomic workstation.

 

The psoas is a muscle that is often stiff due to repeated sitting positions or the  presence of toxins in bodily tissue. It is necessary to stretch it regularly in order  to limit lumbar pain (lumbago) and inguinal inflammation. The iliac psoas is a  muscle of the posterior region of the abdomen that connects the thigh to the trunk. 

étirement du psoas, stretching psoas-iliaque, muscle
The piriformis is a muscle often contracted, located at the gluteal level, it  stabilizes the pelvis and is very close to the sciatic nerve. People easily, and  often wrongly, accuse this nerve of causing pain in the buttock or leg when in  fact, the pain is often caused by a compression or adhesion with the piriformis  muscle. 
étirement piriforme, stretching pyramidal, muscle