Bread dough had risen twice, and waiting for oven to heat. As I picked up pan, it deflated. WHY!?

You may have inadvertently put some pressure on the dough, and that would cause it to deflate.

Don't worry, though, it will rise again. You may have to wait a bit after your oven is not, but it will rise again. The fact that it has already risen even once means that the yeast that you used was good. And it takes the temperatures in the oven, the temperatures used to bake bread, to kill the yeast.

Every time that bread dough is allowed to rise, the resulting crumb becomes finer. So, you bread will have a very fine texture to it. The taste will be the same.

Those rustic breads, the crusty ones with the coarse texture, are the result of the dough rising only once. and

The yeast is over-active and producing a lot of carbon dioxide - room too warm, possibly.

Just punch it down and let it rise in a cooler place, not as long, before you bake it off.

TO MUCH YEAST...IT TOOK ONLY A LITTLE WHILE TO RISE..THEN SAT THERE FOR THE OVEN IT PROBABLY HAD AN AIR POCKET..WHICH WHEN MOVED THE AIR WENT OUT

did u use yeast? that makes dough rise. if u did u may not have used enough.