Use the right chair for back pain relief

Especially if you have to sit for long hours. A proper chair should have good support for your lower back.
If your chair does not provide so, then you can use a curved pillow.
The chair should also be leaning backward a bit. Rest your back on it rather than leaning forward.
If you are working on a computer then the keyboard and chair height should be adjusted properly.
It should be in a way that your thighs remain parallel to the floor and eyes stay in level with the monitor top.
This makes sure that you are in a right posture. If required, you should redesign the car seat.
The new model cars generally have seats that can be easily adjusted to make sure you are comfortable.
If you do not have this feature in your car, use a lumbar pillow whenever you are driving.