Hello, here is the situation.  I am a 28 year old male and in fairly good shape.  The other night, I tried to do a 1 arm push up with my right arm.  I figured it wasn't going to be that hard, since I can do many normal push ups.  However, I wasn't even able to do one, an on my attempt I injured myself.  As I was coming down, I felt two pops or cracks in my lower left back.  These pops or cracks were not immediately painful though.  As I got up, I felt nausea an saw a few stars.  The pain started to come after that.  It is now day 3 an boy does by left rib cage hurt. Most of the pain is on the front of my lower left chest, bottom of the rib cage.  Very tender to the touch, an I feel out of it.  Could It just be a sprain?  I can't fathom the idea that I could actual break or crack a rib just from trying 1.  Thank you for you help.