Sternum pain from grappling?

From my grappling classes and open mat, I get some sternum pain after I have been thrown and landed on too much. I also feel it in my lower ribs. When I say pain, I mean it hurts when pressure is put on it (rib cage and sternum) and if I sneeze or cough. I want to know if anyone else feels this pain and what can I do to prevent it in the future. Thank you!