My 2 year old recently had an x ray on her chest and i noticed what i thought might be some 'free gas' under the left side of her diaphragm (there is big black circle). the x ray report didn't mention this - should i be following this up or not?

Free ?: The location mentioned is where the large intestine crosses and drops down toward the pelvis. It is a common site for gas to accumulate in a pocket on an upright chest x-ray. The only way it would be "free air" would be if there were a bowel perforation & the air was outside a contained organ like the bowel. The kid would be deathly sick. I doubt your reading was accurate.