What organs on your left side of your stomach can cause pain?
Most likely the lower intestine (colon). When the colon is
cramping or is full of gas, it can hurt clear up into the left
chest.
If the pain is low in your abdomen it can be referred pain from
a bad appendix (which is located on the right side.)
The spleen is also on the left side.
If this pain is always present, or does not go away in a day or
two, go see a doctor to rule out anything life-threatening