Hi,
What kind of chart are you making - pie, line, bar, ....?
What version of Excel are you using?
You can add data labels to pivot chart by choose Chart, Chart Option, Data
Labels.
You can add a custom label by calculating the percent in the data range of
the spreadsheet and then using the free download form
http://www.appspro.com/Utilities/ChartLabeler.htm.
However, everytime you refresh the pivot table the data labels will return
to their defaults.
This problem can be avoided by using a Pie chart. In which case you choose
Chart, Chart Options, Data Labels and turn on the Percentage option.
If you use 2007 there are fewer problems.