Stabbing pain

I've been experiencing a lot of stabbing pain in my abdominal area. It spreads all in between my hip bones and sometimes on one side or the other. It worsens with heat from my cars seat heater. Like knifes slowly going from my abdominal area up to my chest. My chest then hurts. Also my breasts were sore but could be related to my period coming up. I also felt nauseous. Do you think it's pms or something to worry about?

I did go to the hospital and they did not find anything wrong.