Hello, I had gone through your problem. Initially you had pain in the left lower abdomen and now you have pain in the left rib cage and it hurts when you take deep breath. Pian while taking deep breath is usually pleuritic pain (due to irritation of the pleura which is a thin layer covering the lungs). This irritation of the pleura can be due to infections in the lungs (pneumonia). Pleuritic pain can also manifest as lower abdominal pain. You had not mentioned if you have any other symptoms like fever and cough. So first thing is to rule out any lung problems and this can be done with a Chest X-ray PA view. and also you can get few blood tests done which may show an elevated total WBC count. if these tests are normal then you can get an ultrasound scan of the abdomen to rule out any abdominal pathology or any sub diaphragmatic pathology. My advice is to consult a physician and get the required investigations and follow his advice. Good luck