Why am i in so much pain please help!!?

im 16 and Ok for a month iv been having back pain threw out my whole back..my neck feels stiff and i have a sharp pain in my upper back and my lower back is like throbbing..i went to a doctor and he took x-rays and he said..i had scoliosis but it wasnt bad enough to cause me pain..and then he just gave me the i dont know look.The past week my back has felt better but tonight i exersised just a little and my back hurt so bad..it was so painfull..im only 16..my back should not be hurting like this without a reason..what could this be