I have a 10 year old pole style building that heaved last winter. 3 or 4 posts around 1 corner are up 3 to 4 inches. Why did it heave after so many years, and are there any tricks to get this thing back down?  I called the builder and he said that he had received a few calls this spring about poles heaving. I could probably live with it the way it is but I want to prevent any further damage. Any advice would help.

Where are you located? Did you have an unusually cold winter for your location?
Do you have a concrete floor in the building?
Since your builder has other buildings that have also heaved, it would seem likely that he is not setting the posts deep enough. This combined with an unusually cold winter that drove the frost line deeper than normal seems the most likely explanation.
As to repair, the first thing I would try would be to hook a backhoe bucket to the top of the worst post and apply downward pressure to see if the added weight might drive the post back down. Now I don't hold a lot of hope for this solution, but since the next step also requires a backhoe, and a lot of digging, you might try that first, just in case. The more likely solution will be to excavate down below the posts, pull them down into position, and pour concrete around the base of these posts, before backfilling.