There is a filename text variable that is available. If you go to Type > Text Variables > Define... you can select it, then hit the Edit Button and seelct the checkbox to include the full path. You might also want to give it a new name so you can have more than one if you need them.
Variables can be inserted into text anywhere you want, but they won't break across lines, columns, or frames, so if there isn't enough space onthe line in which they appear the text will compress and stack up on itself into an unreadable mess.
thank you very much, that solved my problem!