I wish I knew what it was but you're not alone. This is my 4th as well and I don't have it as severe as you, however in the last couple days, I've had the exact same pain you described in the exact location. The only thing the nurse could tell me was that it was probably the baby getting bigger and I'm sensitive to his positions and movements but I don't know. I don't have the bh at the same time but I do have the stabbing burning pain off and on. Hopefully another member can shed some light.
My SIL had rib pain and is very petite. Her OB diagnosed it as inflamed rib cage from the limited space. There is tissue between yur ribs that becomes irritated and inflamed according to he doc. Unfortunately I don't think they did anything other than induce her a couple weeks early due to the pain.
Hello, I'm a lurker and came across your post today.
Hi, I'm lurking from the December EC board.