The complaint of pain, stiffness, clicking, and irritation in the HIP JOINT is very, very common.  If you’ll notice in the picture, there are MANY muscles that cross the hip joint and affect the S-I (sacro-iliac) joint as well!  Muscles and joints, along with ligaments (connections between 2 bones) and tendons (connections between a muscle and a bone) can all be involved with hip issues to varying degrees. 

A couple of things to help with S-I and hip joint mobility and stability: