Currently 18 weeks, 2 days, and for the past couple days, toward the end of the day (4pm and after) I've been having really bad pain in the upper right part of my back, kind of inside the shoulder blade. My breasts have grown some, but not even a whole cup size, and I've gained 1 pound, so I'm not sure what's causing it, or even if it's pregnancy related, but I haven't changed my activities, so I assume it it is. Standing up straight hurts the worst, if I purposely slouch, and and pull my ear to my left shoulder to stretch it it helps, and sitting and lying down help too. Has anyone had this happen or know what it is?