What Causes Swelling Near The Wound After Gall Bladder Surgery?

Hi, I am a 54 yr old Male that a year and half ago had Gall Bladder removed. Not Im having server pain at times and right side is sometimes swell like gall bladder is still there. Pain scale is at 10+ at times and not sure. What is this swelling and how do they test to see if you have a bad liver?