I proofed my yeast and realized it was dead but decided to still make the pizza because I figured flour, tomato sauce and cheese would still taste good.   550 degrees Fahrenheit- 9 mins- 12 inch diameter.   Top and bottom perfect but It still looked dense and undercooked in the middle.   Is this because the yeast was dead?   First attempt was room temperature and second was refrigerator temperature after proofing for 2 days- both doughs were undercooked in the middle. 
It is definitely because the yeast was dead. Leavening creates air pockets in the bread, and these air pockets heat up quickly and help the dough cook evenly. If you look at recipes for unleavened breads, you'll notice that almost all of them call for the dough to be extremely thin so the bread is able to cook evenly from only the heat in the outside air. Unfortunately, pizza dough is usually thicker on top of being weighed down by sauce and toppings. It either needs to be rolled out ultra thin or pre-baked before toppings are added.   You could also try cooking it at a lower temperature for longer than you normally would to make sure the middle has time to cook before the outside gets burnt. Pizza's are recommended to be cooked at a high heat because it gives the dough better oven spring and a nice fluffy interior with a crispy outer crust, but if you're not using any leavening you're not concerned with oven spring at all. 