Hello Kanonathena
This means "I have a dispute or unpleasant matter to settle with you".
A similar Irish phrase is "I have a crow to pluck with you".
It seems to be a reference to picking the last bits of meat off a bone. This is a difficult business; the implication is that settling the dispute will mean a lot of difficult and detailed discussion.
(You'll also find suggestions on the internet that this relates to a custom at Sicilian weddings, but that sounds like a later rationalization to me.)
MrP