Posted: Fri Sep 07, 2012 9:38 am
I had a lot of shortness of breath with both pregnancies, but not that feeling in the back and shoulders you describe. For me it was a case of the babies pushing against the diaphragm/lungs and being anaemic. I took a good iron supplement during my second pregnancy (and she was a smaller baby) and it definitely helped.
Do mention it to the midwife though, maybe you've just strained something? Good luck!