I have this along with upper back pain (occasional) and after a bit of googling it seems like it could be anything from a trapped nerve to a cracked rib, yaaay, lol.
I meant to mention it at my hospital appointment yesterday but they literally kept us waiting so long that we had to rush out for OH to get to work, and we were the only people in the waiting room for over an hour, annoying!
Anyway I read this somewhere else, might help!
"Rib pain can range from mild to extremely sore and tender ribs and is usually felt on the right side, just below the breasts. Mainly occurring in the third trimester, it can be more painful when sitting. Rib pain is caused from the uterus pressing into the abdomen, squashing your ribs, as well as baby kicking or punching the area. The only real ways to help here are to make yourself as comfortable as possible by wearing lose fitting clothes and supporting yourself with cushions when lying down. The pain will likely subside when baby drops (into your pelvic cavity) in preparation for birth. Here is a really effective exercise for temporary relief. Stand facing a wall. With your feet 40cms from the wall, cross your arms in front of your face. Then lean your crossed arms on the wall sliding them up the wall above your head and stretching yourself up as far as possible. Hold the position for as long as comfortable. This lifts the diaphragm and rib cage up"
