You Do Need power plug adapter while traveling from Pitcairn Islands to Pakistan.

Here is Why You Need An Adapter

The outlet and plug type used in Pakistan are C and D and in Pitcairn Islands is I. This is how they look like.

Pitcairn Islands

In Pitcairn Islands, outlets of type I are in use.

Type I

Pakistan

In Pakistan, outlets of type C and D are in use.

Type C

Type D