I've had it. It reared its head last fall when I started to take up running - very sore at left iliac crest next morning, got progressively worse from run to run, until I quit running after about 5 outings.
Got to the doctor later, got X-rayed, turns out I have bone spurs right where the pain occurs. Not sure what caused them.
I've noticed mild soreness there the day after a big, tough hike, much as weatherman says. But for the most part, it has not affected my hiking, fingers crossed.
I encourage you to check in with a doctor about it if you haven't yet, hiking lady. Good luck!