Iliolumbar Syndrome

Очень похоже на мои симптомы. При растяжении разрывах воспалении iliolumbar ligament возникает боль в районе multifidus triangle (the facet joints, erector spinae muscles, lumbar fascia, quadratus lumborum and the iliolumbar ligaments)

Painful attacks are often brought on by physical exercise involving bending and twisting of the lumbar spine. Some individuals complain of pain only after prolonged sitting or standing or for a brief period in the morning after getting out of bed. Pain may also be experienced in the hip or groin area. 

http://www.caringmedical.com/conditions/Iliolumbar_Syndrome.htm