|okay, I just left a long message and it got deleted when I went to post it....so I will make this one brief. I had a similar problem - pain in my right groin especially after sitting - took 12 years to diagnose so hopefully you will have better luck. I saw a podiatrist, chiropractor, osteopath, orthopedic surgeon and all of them told me I had a "groin strain". After 12 years of this I decided to get an MRI myself and took the results to a highly recommended surgeon...then got a second opinion. Both Dr.s agree that I have congential hip dysplasia (shallow hip sockets) which have caused the cartiledge to wear out prematurely, labral tear and bone cysts. I need a hip replacement.
I would suggest you get an MRI which will show any damage and an xray to show your joint mechanics. Impingement is when a tear in the labrum gets caught in the joint during particular movement - it can cause the pain you describe. In fact, when I told the surgeon that it hurts after sitting he said this is commonly referred to as "start up pain".
I have had herniated discs and sciatica but the pain I am having is like someone is jabbing an icepick in my groin....unexpectedly.
I just joined this post today and would like to know how things turn out for you.