I've had these!!!! I'm six weeks away from giving birth for the second time and I swear to GOD I've feel like I've been through every little scare possible! I'm probably completely normal and just a tad stressed! I went to the Early Pregnancy unit and they hooked me up to monitors, took blood and urine for tests, listened to the heart beat etc. While I was there I had the pains and they monitored me during them. It felt like I was being stabbed with a darning needle in my side and the pain went straight across my stomach and under my other arm.
It was ligament pain as my baby gained a lot of weight in two weeks, which I have been told is also completely normal, and it put a lot pressure on the ligaments that run from under each arm into the groin area. Now I know what they are, i just take paracetamol and put my feet up.
If you're not 100% convinced, go to see your midwife, they really don't mind what time, day or night you ring or turn up, better to be safe than sorry!