Hi. I am not completely sure of your question and when you have the back problems, but I know during the first few days of my period and the day before I have extreme lower back pain. It is always how I know when my period is about to start.
Since going on the pill it hasn't been as bad, but when I was younger I would be woken in the night crying from the pain.. and then the next morning I would have started bleeding.
Studying for long periods is also hard during my period as I get the lower back pain. It makes me feel nauseous.
I take lots of pain-killers during the first 24-36 hours of each period. It is all I can do if I have any work that needs to be done in those days. i can't see how it is a problem.
and for me the reason for the back pain is due to endometrisosis. apparantly back pain with periods is one of the common signs of endo.