I woke up at about 4 in the morning with horrible chest pain right between my boobs and was up for at least 2 hours. It felt like my breast plate was ripping apart while simultaneously sinking in, making it hard to breathe. I found that it didn't hurt as bad while I was sitting up as it did when I was lying down. Googled it and it seems to be either heartburn from hell or my rib cage expanding to make room for the baby and organs. Has anyone else experienced this??