Set up my desk and daily movement to ease stiffness

Help me reduce stiffness and discomfort from sitting at a desk. Where I work: [e.g. "laptop at kitchen table", "office desk with monitor", "standing desk"] Equipment I have: [CHAIR, MONITOR, KEYBOARD, MOUSE, LAPTOP STAND] Hours at the desk per day: [NUMBER] Where I feel it: [e.g. "neck and shoulders by afternoon", "lower back", "wrists"] Budget for changes: [AMOUNT or "nothing - use what I have"] Give me: 1. A setup checklist with how to check each item: chair height and support, screen height and distance, keyboard and mouse position, lighting, laptop fixes (books as a stand, external keyboard). 2. Free fixes using items around the house, then low-cost upgrades in priority order. 3. A movement break plan: when to break and 6-8 short stretches or movements (1-3 minutes total) I can do at my desk, with simple instructions. 4. Habits that help: switching positions, walking calls, eye breaks (look away at something far periodically). 5. A one-week check-in to see what's working. Keep stretches gentle and pain-free. Tell me to see a doctor or physical therapist if pain is sharp, getting worse, spreads down an arm or leg, or comes with numbness, tingling, or weakness.