My 89 yr old mother hurt her back somehow and is in a lot of pain on the right side from her ribs to her hip. She thought she did it getting the mail and she turned wrong. The Dr put her on muscle relaxers last night, she has taken three already and has not helped the pain. She can hardly move. How long do these take to work? She does have an appt tomorrow if I can get her there with all the pain. If she sits still she is ok it’s when she moves it really hurts.