When some wound swells up, reddens & hurts, it may be a sign of inflammation. But generally speaking, inflammation is the response of your body's immune system to an irritant. The offending irritant could be a germ, as well as a foreign object, like a splinter in your finger.
This means that an inflammation does not only start when, for example, a wound has been infected by bacteria, isn't healing properly, or is oozing pus. It starts when your...