OMG! I experienced that for the first time today, I'm 17&4 and the pain lasted at least 20 mins! I got scared and drove myself to the ER, they did blood work, ekg, and xray. Everything came back great, it seemed like every time I inhaled the sharp pain was stabbing me. The Dr said it just my chest and lung area expanding getting ready for the baby. But hell it felt like I was having a heart attack ....seriously!
I had that same sharp pain, under my left breast. It almost feels under the rib. It happened during both my pregnancies. It was a pulled abdominal muscle, I had to stop working. Ask your doctor if you have it. I had to stop using my left arm/hand for anything. I would unload the dishwasher and the pain would come back. The less you do the better it will be. I used a heating pad on that high rib area for 20 min. like 5 times a day! The good news is - that once you deliver your baby, the pain should be gone in a week or two. Hope that helped