pain in lower back please help!

the past couple days i have been waking up with pain in my lower back where my kidney would be. at first i thought i was maybe sleeping in one positin to long, but this morning when i went to the bathroom. it hurt to do kegals almost. like the pressure of pulling it in hurt were my kidney would be. ok let me say first of all. saturday i fell down the steps and landed on my butt really hard, which in turn left me with a bruised butt bone, and it felt like it jarred my back a little bit. but other than the butt bone, i had no back problems. i have never had any problems with my kidneys at all. i am 26 years old and i am healthy. i am really scared now that somthig is seriously wrong. it isn't normal for your kidney to hurt. another question, if it was my kidney actually, wouldn't it hurt if i pressed where my kidney is? the pain actually eased a little bit. now it is to the point to where it just feels stiff. like it would getting up sore from sleeping. i am at a loss here, and i am not sure what i should do.if i should see if it persits or what it should be. i need some helpful advice on this. because i am a healthy person.