Why Does My Lower Back Hurt When I Sit Down?

Lower back pain when sitting typically occurs due to poor posture and increased pressure on spinal discs. Sitting increases disc pressure by up to 40% compared to standing, compressing the lumbar spine and straining surrounding muscles. Poor chair ergonomics, slouching, or sitting for extended periods can worsen this pressure. Weak core muscles also contribute by failing to properly support the spine. Additional factors include herniated discs, sciatica, or muscle imbalances that become more pronounced in seated positions. The hip flexors can tighten from prolonged sitting, pulling on the lower back. Taking breaks every 30 minutes and using proper lumbar support can help alleviate symptoms.