Is there a way to link artwork to a repeat tile? Say if I want to exit out of the pattern and work on the original artwork or do I have to go into pattern editing mode everytime I want to make changes?
You must go into Pattern Editing mode to edit patterns. Pattern creation typically causes, and demands, the breaking of any links when the tile is initially created.
Patterns can not contain linked content. Even things such as internal document links, i.e. symbols, will be broken for pattern tiles.