How many times have Earth's magnetic poles shifted and will they continue to do so in the future?

This has happened quite a few times over the ages -- at least 180 times in the last 83 million years.
There's no reason to suppose that it cannot happen again, and some would say that it's overdue, since the average interval between pole reversals is about 450,000 years, and the last reversal happened almost twice as long ago as that.

https://en.wikipedia.org/wiki/Geomagnetic_reversal