This happened to me a couple month ago. Had to stop deadlifting and doing any standing rows for weeks. It is just now better. her is a thread I made over on another site after it happened. Doc said I tore the muscle away from my bottom rib.
Last week I was doing my lighter deadlift routine and may have had my belt alittle too tight but I dont know if that had anything to do with it. I was on my last set nothing major heavy but did 405x12 and felt something kinda pull in my stomach on my side up near my ribcage. After the set I realized that it was hurting pretty good and stayed sore for a few days. It felt like it was almost gone so this week I felt strong and planned on going heavy. Well after only 2 reps with 405 it hurt so bad I stopped. Well, this sob is soo damn sore that it feels like I may have seperated a muscle from my ribcage. I sneezed this morning and almost brought me to my knees.
Has anyone ever done this and WTF could it be. I guess I will have to lay off DL for a few weeks or so. I swear I am the most injury prone bastard I know. Bad shoulders, bad elbows and now this stomach **** I cant gain for losing!
Yep.. sounds EXACTLY the same! And the doc told me the same thing. Damn.
Even the "injury prone" part is becoming my life! Shoulders, knees and now this. My elbows are still good though!

Thx for sharing how long you were feeling it though. I've been wondering.. sucks ass that it's happened right before summer! I was working damn hard! Ah well.. guess I'll keep the protein over 300 and try to find some light exercises to maintain for a while.