What could this be?

I'm 18, so I think I'm a little young for debilitating illnesses but my father in law thinks it's sciatica or however it's spelled. Anyways my hips are extremely sore, it feels like from my lower back and hips is this awful shooting pain that goes all the way down my lower thigh into my calf. Only on one leg, that's not like some kind of pregnancy symptom is it?