im sorry that you have to read all this but i really want to know
my arm aches somtimes well alot latley its my left one its just like a dull ache starting from the hand to the middle of my arm i havent sprained it im 12 and a half years old my hands are skinny my arm is a bit so i think i would be able to feel if there was somthing there i have had a prodd around and cant feel anything :0 its confusing cos i dont know whats wrong it somtimes feels a tiny i mean a tiny weeny bit weak and a tiny weeny bir stiff i sleep on this arm but its never affected me before help

also could it be cancer?