@Tarajeane I have the exact same groin pain. It's going from sitting to standing, I feel it when I lift my leg straight, and I still have a lot of problems when I go from bent knees on my side to laying my leg out straight on my back. I have problems with my thigh muscles spasming, kindof like a charley horse but in the full of my thigh. The PT says she's seen it before and that in time it will go away. And I am stiffest in the morning as well. Moving seems to be better than being stationary.
In my research, even on these boards, It's possible it has to do with the Iliopsoas Tendon. It goes right over the acetabular cup and is involved in "dancer's hip". I have felt it slip off (without pain) when I swung my leg slightly around over the tub edge. I believe it's what popped off that night I had the full on hip spasm and was GREATLY painful.
I have found not sitting in my recliner has helped. Instead I lay more flat on my couch allowing my hip to not sit in flexion. Work last week was so long and I know that all the sitting, even though I alternate sitting and standing really inflamed it. I spent the weekend on the couch with ice packs.
I have started walking without my cane too, I have noticed it got worse when I went from walker to cane and then cane to unassisted. I'm giving myself a full 12 weeks to see this get better. It's hard. I'm not a patient person.