Low back pain?

Hi everyone. I will be 12 weeks on Thursday, and my lower back is sore. I heard the heart beat at 11 weeks exactly, and it was good and strong. I have still been moody and have sore breasts. My nausea has let up a lot. I felt nauseous each day a little, but haven't been sick in a few weeks. Today has been a good day with respect to nausea... Anyway. I am wondering if the backaches are a normal part of pregnancy or if I should be worried. This is my 1st. I'm due January 21st.