Pill causing back ache?

Is it possible for the pill to cause back ache? I've taken this pill before and never had this. I've never had backache like this before except for when I was pregnant. This is my first month back on the pill(been taking it for a full month) and my first period while on it is due in 2 days, could this be the because of the pill? It's been sore all day but I'm not sure if I slept in a weird way or something.