Groin pain – beginnings of stress fracture?

I am 35 and ran two marathons last summer. This winter is the first time I am training at all. Recently I noticed a feeling of discomfort (I hesitate to call it pain, since it is so mild) in my groin area on the left side only. There is no pain when I run, even long distances, but the discomfort is quite noticeable the evening after my big workouts. I have been reading a lot about femoral neck stress fractures, which share many of the same symptoms. I have also read that this sort of injury can manifest very gradually, and that it is best to treat it early (with complete rest), rather than continue training hard to “make sure” and thereby cause oneself a much mor serious injury. Since rest can’t hurt, what sort of time are we talking about when trying to make sure that one is ready to resume training after a suspected stress fracture. Has anyone out there had a similar experience? Although I absolutely hate the idea of a complete break from running for 2-3 weeks or more, I would vastly prefer this to a serious stress fracture and several months on crutches, after which I may never run as well again. I would really appreciate knowing if anyone out there has been faced with a similar dilemma and could give me some good advise.