Left side upper abdominal pain, some chest pain??

Ok...a couple of months ago I started having chest pain (usually on the left side..and somewhat sharp)..used to have my left shoulder and arm hurt and so on...I went do a doctor, did my complete bloodwork, also an EKG (all normal)..Then I went to see a cardiologist and also did an EKG..and checkup - the cardio said It was nothing wrong with my heart (that should be a relief,no?)..Ok..After some time i started having upper pain in my back (also left side)..I went to a Radiologist...did an Xray and he told me I had a "walking pneumonia"-went to the doc and he gave me antibiotics to treat it. I haven't finished the treatment yet, and now, even if I don't have back pain or neck pain ..or arm pain anymore..Sometimes I still feel some pain in my chest (right or left side) and I am getting some upper abdominal pain in the center and left side (kinda like just under and below the ribs). I don't smoke..I don't drink..Don't drink coffe...So? any ideas?