I wonder if anyone is following this thread because I have much to add.  Over 32 years I have seen 18 doctors about groin pain and most of them offered no opinion while one or two misdiagnosed it.  When I caused a bad and lasting flair up a year ago it became apparent that the problem was my psoas, which doctors know little about, and it seems that those of you here are describing psoas injuries.  I have done enough research on this muscle to do a masters thesis.  My symptoms have included but are not limited to: general groin pain (sharp) which occurs after rather than during exercise in many cases or from simply walking; discomfort while sitting with a “fullness” in the groin area; extremely painful external rotation of the leg; pain when foam rolling my rectus femoris; sleeping with my leg hiked; internal snapping hip.  Google Thomas test to determine psoas tightness.    Sit straight up in a chair and lift your straightened leg completely off it.  If you experience groin pain it’s due to psoas tendonitis.