To loosen tight hamstrings and lower back, incorporate regular stretching and strengthening exercises into your routine. Stretch the hamstrings with exercises like standing and seated hamstring stretches. For the lower back, try the Child's Pose and Pelvic Tilts. Strengthen the core muscles to support the lower back. Stay hydrated and maintain good posture. Consult a healthcare professional or physical therapist for a personalized plan, and consider massage therapy or yoga for added flexibility and relaxation.