Suggest Treatment For Lower Back Pain After An Injury

my teenager somehow fell on the first two stairs. I did not see it but I heard a thud. When I got to the stairs, she was laying down crying, unable to get up. Her left side of the body seems to have taken the hit and her shoulder is a 10 burning pain she has never had before. Her lower back and hip hurt too, but much less. She took the fall at about 12:55pm. Its almost an hour later, she is still on the floor - propped up by pillows and still hurting. I am not able to lift her easily/gently and she does not want to be moved so we are keeping her where she fell. She is able to move her fingers and toes and she says she bumped her head lightly trying to catch herself in the fall. She has chronic migraines so I gave her 400 mg of Ibuprofen and some sips of coke to wash it down with just to ease the pain enough to move her. Her head feels better and her hip/back feel bruised but not so bad but her shoulder has not changed pain levels. Movement takes the pain to unbearable levels so as long as she stays still she is doable. With this kind of pain I don't want to put her in the car to wait in the emergency room for hours on end so I was planning to take her to urgent care at 4pm when they open. How much medicine can I give her for pain until then?