Mid-back Pain More Condition_symptoms Why Do I Have Lower And Mid Back Pain?

Why do I have lower and mid back pain? - mid-back pain more condition_symptoms

I just had a baby 6 weeks ago. I had bad pains in my back when I was pregnant about everything. This was my second child. However, a boy and I also have a 3-year-old daughter. Would it be a spinal or something else?