Serious Back Pain, and im Young!!?

I am a 14 year old male, im not really that active but im not fat, today i was running around with my dog and i sat down and suddenly i felt this sharp pain i stood up and it hurt badly, i tried to crack my back but it didnt work then i told my mom if she could rub Bengay on my back it didnt do anything, when i sit down or lay down it doesnt hurt but when i stand up it hurts badly, and for me to walk and for it to not hurt when i walk i have to walk hunchback or my back alllll the way back, i tried already to crack it various ways but it wont work, the pain calmed down after i layed down a while then it came back furiously, tommorow is halloween and i dont want to ruin it for my family, i want to get better i want the pain to stop, its not a muscle pain(atleast it doesnt feel like it) it feels like my spine or something, please help me please this back pain hurts!!!