Whenever there is pain in left side of abdomen one should think of possible organs there, lungs, stomach, pancreas, descending colon, sigmoid colon, uterus in ladies, fallopian tube, ovaries can cause pain, kidney related issues which cause pain, ureter, abdominal aorta can cause pain on left side. If there is growth like cancer which causes excruciating pai. usually inflammatory symptoms are present that is pnuemonia, pancreas effected can cause pain, kidneys effectd it coukd cause upper adominal pain . The area affected is the cause involved.In a simple case of gastritis Apple does help.