Groin strain?

Another boring injury question!

So did my first marathon.  Was stiff the next day - fine, expected that.  But my right hip was extra stiff and this has now moved into my groin area (right side only), which feels stiff and incredibly weak, and sore.  I've been limping since the marathon 9 days ago. 

is it groin strain?  How long will it take to heal?

I'm assuming it's an actual injury as my left side is completely fine.

I'm not planning on running for another 3 weeks anyway, but hope I will be able to by then?

I've been swimming a couple of times but want to start cycling/rowing again next week - is this advised?