Back pain at 5 weeks, 3 days

Katie • A mother to a sweet for year old son and expecting baby #2 in July 2015
Since getting my BFP the other day, I have had some very uncomfortable lower back pain. I experienced regular cramps with my first this early on, but never back pain. The last time I felt this dull pain outside of pregnancy a few months back, an ultrasound revealed that I had cysts on my ovaries. Could this still be the case? Is it dangerous to my baby if I have cysts on my ovaries?