Sore rib... Normal?

I am 26 weeks pregnant and my rib is killing me, just under my right boob. I actually have a bruise on the area. 
I have had this for 3 weeks, I have been ignoring it as friends and family have said its nothing to worry about and probably just the baby kicking. 
It's definitely not him kicking, it's a constant pain and when I lift my arms above my head, it feels like my rib is going to pop out my body. 
Has anyone experienced this?