dear texaswildrose- in brief: i too have l5s1 issues- a degenerated, bulged, torn l5s1. they say that the disc itself can cause IS joint pain which could entail groin issues. I have pain from my lower center back through my buttucks and hips ans sometimes into the legs/feet. the docs say this is the nerves related to the l5s1 and the disc itself causing all this pain. the phys therapists tried working on the SI stuff but didn't change things much, unfortunately.
sitting is the worst for me and i avoid bending as much as possible. i did do xray guided injections into the si joints and that calmed things down. then i decided that 7 injections in 8 months was enough cortisone for me!
hope this helps/feel free to ask more ?s-