Thanks for the photos. It looks like a lot of your solder joints should be reflowed. I would reflow all of them for good measure. Use a bit more heat (leave the iron on the joint a bit longer) and less solder this time.
Your power amp chip is working because you get a buzz on the speaker when you touch the pins of the amp chip. The problem is on the digital sides somewhere. How is the 5V power rail?
-Brach