My lower back started aching around two in the afternoon every day. Not sharp pain — just a dull, nagging stiffness that made me shift in my chair every few minutes. I blamed the chair. I bought a lumbar cushion. I tried a standing desk. The standing desk helped but I still felt tight by the end of the day. A physical therapist friend watched me sit for five minutes and said my hips were the problem, not my back.

Sitting shortens your hip flexors — the muscles at the front of your hip that pull your knees toward your chest. When these muscles get tight, they pull on your pelvis, which tilts forward, which arches your lower back, which causes that afternoon ache. Stretching your chest and the front of your shoulders helps too, because hunching forward rounds your upper back and tightens everything across the front.

Here are four stretches that take five minutes total. I do them once mid-morning and once mid-afternoon. The back pain is gone.

1. Doorway Chest Stretch (60 seconds)

Stand in a doorway. Place your forearms on the doorframe at about shoulder height, elbows bent at ninety degrees. Lean forward gently until you feel a stretch across your chest and the front of your shoulders. Hold for thirty seconds. Then slide your arms up a few inches higher on the frame and lean forward again for another thirty seconds — this hits a different set of fibers in the chest.

2. Half-Kneeling Hip Flexor Stretch (60 seconds per side)

Kneel on one knee with the other foot flat on the floor in front of you, like you are about to propose. Squeeze your glutes — the butt muscle on the kneeling side — and shift your hips forward slightly. You should feel the stretch deep in the front of the kneeling hip. Keep your torso upright — do not lean forward. Hold for sixty seconds and switch sides.

3. Seated Spinal Twist (30 seconds per side)

Sit in your chair, feet flat on the floor. Cross your right ankle over your left knee. Place your left hand on your right knee and your right hand on the back of the chair. Gently twist to the right, looking over your right shoulder. Hold for thirty seconds. Switch sides. This unwinds the tension that builds in the mid-back from hunching forward.

4. Standing Forward Fold (60 seconds)

Stand up, feet hip-width apart. Bend your knees slightly — locking them strains the lower back. Fold forward from the hips, let your arms dangle toward the floor, and let your head hang heavy. Do not try to touch your toes. Just hang there and breathe. This decompresses the spine after hours of vertical compression from sitting.

The whole sequence takes five minutes. I set a timer on my phone. After about a week of doing this twice a day, the two p.m. back ache stopped showing up. The stretches did more than a three-hundred-dollar chair ever did.