A common reason your back may hurt is from bad posture while seated. Sitting in a slouched or hunched over position can put strain on the discs — the fluid-filled cushions that protect the vertebrae from rubbing together. This may be worsened by an underlying medical condition.
The most common cause of lower back pain is postural stress. This is why lower back pain is frequently brought on by sleeping in the wrong position, prolonged bending, heavy lifting, or even standing or lying down in a poor, rounded back position. According to Cornell University Department of Ergonomics, up to 90% more pressure is put on your back when you sit versus when you stand. There are several reasons why, the first being that if you're like most Americans, you habitually sit in ways that cause tension and imbalance in your back and neck. This applies to sitting at work, in the car, and at home.
A person might injure their lower back while lifting something incorrectly, leading to a strain or sprain in the area. The injury might instead result from trauma, sustained during sports or from a car accident, for example.
When you sit in a soft chair the seat usually sinks in and causes the same effect as when you're slouching in a chair. It is nearly impossible to sit in a good position on a very soft surface.
Over time this will cause the ligaments and muscles will stretch to a point where they can hurt and if you have any discs that's a little bit worn they will also start to moan. Visit https://bodybilt.com/what-are-good-office-desk-chairs-for-peoples-upper-backs/ to know about what are good office/desk chairs for people's upper backs.