What Causes Back Pain And Tightness In The Abdomen After Giving Birth?

Hi, I am a 19 year old female, who just had a baby 3 months ago. For the past week I've been having back pain, tightness of the stomach and lime green poop. I have gone to the hospital they did a CT scan, and blood work and everything came back normal. but on top of these I'm super dizzy, light headed and very pale.