SI joint pain happens when the sacroiliac joint, which connects the spine to the pelvis, becomes irritated or misaligned. It can cause discomfort in the lower back, hips, or buttocks, and sometimes radiate down the legs. Weak core muscles, poor posture, or uneven movement can increase stress on this joint. Mobility helps relieve SI joint pain by improving the movement and balance of the hips, spine, and pelvis. When these areas move freely, less stress is placed on the SI joint. Gentle mobility