You're right, some girls can feel when they ovulate, but if its always on one side I don't think that's what you're feeling (but you've only had it about twice - two months - maybe you had a fluke). Or maybe you just get a certain cramp when you ovulate, like you would when you menstrate. But if its only happened twice and it's not an intense pain I wouldn't worry about it. IF it gets worse, go see your doctor.