I thought the same thing Catrin did when I first started running. For my hips to hurt that bad I assumed something about my body wasn't meant to run. It doesn't happen over night it took me a couple of years to work up to being able to run more comfortably. I work really hard on running form and maintaining good alignment and that helps tremendously. I found out my extreme hip pain I originally suffered from was from what I now call "pendulum syndrome". Its when you see someone running and their whole body starting at their feet sort of swings back and forth with every running step. That's really bad form but it's very correctable. Honestly I didn't have too much trouble with the cardio part of running but I can tell now I can sprint easier and longer on the bike. I think that is due to my running since I don't get winded as easily as I used to. I don't think I have the ideal running build but work with what God gave you.