I just put together a new bike, and after a few days of riding it quite a bit (i'll probably get up to 200kms today) it is suddenly riding a little bit less awesome than it was before- there is some drag happening somewhere in the back and i can't quite figure out why. I think the back wheel seems to be a tiny bit out of true- it is used, and i think it was in true when i got it, but it also spent a year in my garage which might have made a difference. anyways; before i keep rambling

1) How often do you true wheels? is this less of an issue if your riding a fix gear and don't have to worry about the back wheel rubbing on the brakes?

2) Is it possible for my chain to be too tight? I think i might just need a new bb.

3) are there any other common problems that might be causing this that noob like myself might be unaware of? I think my chain line (and back wheel) is pretty straight- but to accomodate that my wheel is a little bit closer to the left than say, my top tube. I don't see why that would be a problem, but i figure i'd mention it.