The pain of sacroiliitis most often occurs in the buttocks and lower back. It also can affect the legs, groin and even the feet. The pain can improve with movement. The following can make sacroiliitis pain worse:  Sleeping or sitting for a long time. Standing a long time. Having more weight on one leg than the other. Stair climbing. Running. Taking large steps when moving forward. 
pain sacroiliitis occurs buttocks lower back  can affect legs  groin feet  pain can improve movement  following can sacroiliitis pain worse:  sleeping sitting long time  standing long time  weight leg other  stair climbing  running  taking large steps moving forward
sacroiliitis