I'm 21.5 weeks. All day I have had excruciating lower back pains. It's been off an on. It will go away from 15-20 minutes then come back. It has had me in tears all day. I haven't had any cramping except for diarrhea cramps. Has anyone else dealt with this? Can you have contractions in your back only? Baby has been moving so he's ok. This is baby 5 and I have never had this problem before.