So, here's the story.

I bought my 2010 Surly Steamroller new in April. About a month ago, I noticed some resistance and it was getting harder and harder to pedal. I took it to the LBS and they said the rear wheel bearings needed repacking. Ok, fine. It was seemingly fixed then. Recently, I switched to a smaller toothed cog. Sometime after this happened, I started being able to hear the chain as it spun around. This was weird to me since before it had been dead silent. I took it back to the LBS and they said I need a new chain. Ok, I had only put about 2,000 miles on, but whatever, I need a new chain. I bought the SRAM PC 870. The new chain did not fix the noise. It did not fix the slight vibration I can feel through the pedals either.

The chain sounds like this without the pinging. The bike in the video is not mine:

http://www.youtube.com/watch?v=e5UfCsTKbQY

I've taken the bike to four different shops and they all tell me nothing is wrong with the bike. I can feel it though! I feel like it's slowing me down!

One shop said the chainline is not completely straight. It's just so very slightly off. Should I get a new chainring?

I've tried having the chain both really tight and really loose and the noise is still there.

The chain and chainring are both 3/32" I think. Do you think the cog is 1/8"? Would that cause the problem? I don't have the tools to remove it or else I'd look.

I feel like the bike shouldn't have these problems after half a year of use!