It's always possible that something is bothering him, but I think history proves otherwise. In terms of overall production, this first half is very similar to his past first halves. I think that's the main reason why you don't see any concern over CC.
As for the velocity dip, according to fangraphs, here are his average fastball velocities from 2007 on.
2007: 92.9
2008: 93.7
2009: 94.2
2010: 93.1
According to PitchFX, in his last start, his average fastball velocity was in the mid 93s (depends on whether you look at his four seamer or sinker), and he topped out at 95.4.
According to the data, I'm not too concerned about his velocity, especially with the warmer summer months ahead.
As for the home runs, sure, it could be a sign of a bigger problem, but I think it's more likely that it has to do with poor location with his fastball, and not enough downward action on his changeup. I can't prove anything statistically, but I think there's a very good chance the increased home run rate is relatively flukey, and as the season progresses into a larger sampling, it will correct itself as CC's command hopefully improves.