You need to see a doctor as soon as possible. The back ache and the pain you are experiencing in your legs may be caused by underlying medical conditions. Only the doctor can prescribe the right medicine after proper diagnosis.
You require real medical advise from a trained licensed healthcare professional. While we sympathize with you the only useful advise anyone here can provide is above. Do you really think anyone with those credentials is here in the middle of the night(USA) to actually help you?