What could be happening?

Stephanie • Boyfriend: 12/29/2014 - Forever :) Baby Boy - 09/25/2016 and pregnant with baby #2 due 11/20/2017

I'm only 26 weeks pregnant. Second baby. And I swear I'm having contractions or something. But it hurts my entire spine? And my chest as well? Anyone else experience this and/or know what's going on?