rib pain

I'm 37 weeks and for the past few days or so I've been getting a lot of pain in my rib it feels like the muscles in my ribs are pulled thr only reason why I know the feeling is because I've pulled the muscles in my ribs twice in the past year. what could possibly be causing this? is it because the baby is jamming himself in my ribs? I'm going to talk to my dr about it on Wednesday but I want to know if anyone else has experienced this I'm a ftm so I have no experience