My lower back has been hurting so bad for 3 days now i can't bend or twist but i know i didn't twist it ?

Back strain: I sounds as if you have strained your back. This can sometimes occurred even with normal activities. The key to reducing pain is to remain active as possible while avoiding activities which can worsen pain. If the pain persists you may need a muscle relaxer. If you have any fever, urine or stool incontinence, numbness in the legs or rectal/genital area you must be evaluated immediately.