Why does my lower back hurt when sitting but not when standing?

Lower back pain that occurs when sitting but not standing can be due to how sitting affects your spine and muscles. Sitting can increase pressure on the lower back, especially if you have poor posture or sit for long periods.

1. Pressure on the Spine: When you sit, especially with a slouched posture, your spine can flex more, which may lead to discomfort. This is because sitting changes the way your back is aligned and increases the load on certain parts of the spine.

2. Muscle Strain: Sitting for too long can also cause your back muscles to become tired and strained, leading to pain. Standing up can relieve this strain, as it allows your spine to return to a more natural position and your muscles to relax.

3. Posture: Good posture can help reduce this pain. If you sit with your back straight and your feet flat on the floor, it can lessen the pressure on your back.

Understanding these factors can help you find ways to manage or reduce your lower back pain when sitting. Consider making adjustments to your sitting posture or taking regular breaks to stand and stretch.