What Causes Pain In Torso, Upper And Lower Back?

hello im kendra im 12 a girl im sick stuffed nose bad cough and i have back pains see i got a rash its gone now but they were little pink dots now today ive had sharp pains in myy torso chest and upper back and lower right side in still sick i have them still in my upper back but its not a sore back it wont go away and i need help it hurts alot and i need to no to tell my mom to tell a doctor ohh and ive already had my period hop u can help me thnks