My head, arms, legs, back, thigh aches..?

i'm 14 years old, i have pains and it really troubles me.it's been a long time now. it's not some kind of serious problem is it?pls tell me not. I'm really scared.it's a kind of pain you get when you do exercise but i don't exercise. and sometimes a sharp pain would shot through my arm to my thumb. pls. tell me it's not serious