How do you fix lower back pain that only shows up after sitting all day?

Pain that appears with prolonged sitting and eases with movement usually responds to three things. Change position often — the best posture is the next one, and thirty minutes is a reasonable interval. Strengthen the hips and posterior chain, since weak glutes shift load onto the lower back; hip hinges, glute bridges and split squats are the staples. Build core endurance rather than doing crunches, which often aggravate it — dead bugs, side planks and bird dogs are better. Persistent pain, pain radiating down a leg, or numbness needs proper assessment rather than internet exercises.