"One of the common causes of lower back pain is Sacroiliac Joint dysfunction (SI joint pain)

The Sacroiliac Joint is an important link between the spine and the pelvis.  These joints need to allow a few degrees of movement in order to be able to do activities of daily life.  Instability of the SIJ (too much movement in the joint) or stiffness of the joint, resulting in too little movement, can lead to pain in the  lower back, hip, buttock and even referred pain to the leg.  Sacroiliac dysfunction can be caused by several factors including muscle weakness, postural problems and osteoarthritis.

Your physiotherapist can help!"

http://physioworks.com.au/injuries-conditions-1/sacroiliac-joint-pain

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