Pain in my Upper right thigh and leg?

I just woke up one day and my right thigh hurt. It hurt to sit and I had to adjust myself so much in school. I am 16 male. It also hurt to walk for about 30 seconds then the pain would go away and then I would sit and come back. It's been about 2-3 months everyday and it hurts to Neal down and crotch down and it's also now spreading to my leg what can this be? I have no previous injuries or surgery in my leg. It's just my whole right thigh and leg my left is perfectly fine please help