The good news

The good news is that it looks like there is nothing seriously wrong with my bike. The noise I was hearing was just sand and grit still stuck in the chain. The mechanic at the shop was kind enough to break the chain and put the whole thing in the "chemical bath" while I was at the shop. My attempts at cleaning just weren't thorough enough to get it all out. This particular mechanic (I believe his name is Nathan) is amazing. Sometimes finding a bike mechanic is like finding a doctor. You want someone that listens to you, takes you seriously when you propose what you think is wrong etc. He is really good a diagnosing what might be wrong with your bike and always takes the time to explain it to you.

So, still getting a bit of noise from the chain, but it just needs to be ridden a bit to work the rest of the grit out.