I have a groin pull that became a problem two years ago when I was training for my first 5k. I went to physical therapy and it seemed to improve over time. The interesting thing is that I could still feel it when I would run over to the high school but when I got to the track and started doing sprints it felt like it stretched out and stopped bothering me. The next spring I started running again and the groin pull came back but not as bad as before and I was able to keep running by slightly modifying my form. It did slow me down for my annual 5k though and it is still bothering me off and on. I haven't been running but sometimes I can feel it and sometimes I can't.