I pierced my belly button 5 days ago its not really sore but its quite red and itches like a healing wound does but there is no pus present... is it infected or just healing?

Healing. Try putting some salt water on it once a day to prevent infection :)

The itching means that it's healing. If there's no puss that means that there may not be anymore dead tissue in that area that needs to be released. Seems like your piercing is healing fine. Nothing to worry about. The redness is natural, sea soaks should encourage it to turn to your original skin color.