Twinges in lower left back?

So I was sitting on the couch last night when I suddenly started having twinges and sharp, mild pain in my lower left back. It lasted for about five minutes, then eventually only happened when I deliberately leaned back with slight pain, and eventually stopped completely. This all happened within the span of maybe 10 to 20 minutes. I don't think this is a sign because I've never heard of it happening, but I'm still confused and curious as to what you all think could be going on. My cycle ranges between 30 to 35 days.