back, chest and rib pain?

Hi ladies, every now and then I have an episode where my ribs, chest (sternum) and my back (sort of between the shoulder blades) get a pain like someone is poking their fingers into my spine and ribs. I would say it's not sharp but more like a cramp. It makes me feel sick and only goes away if I lie down. I think it's possibly nerve pain maybe something is pinching when my ribs are expanding? I'm 30 weeks and I have an appointment tomorrow morning with my doc but just wanted some peace of mind that I'm not the only one experiencing this?