I've got a 1983 Bianchi Nuovo that I converted to a fixed gear last year. It's been my commuter bike ever since, and I love it.

Today on the way home, I really messed up my drivetrain. I had a set of headphones in my back pocket (the little ear plug kind) and they fell out and were quickly sucked up into the rear wheel. I didn't actually skid to a halt, but the rear wheel made a horrible clanging noise coming from the spokes, so I grabbed a fistfull of brake and stopped myself.

When I examined the back wheel, the headphones were annihilated and the chain had dropped between the cog and the spokes. There isn't much space between my cog and spokes, so they were really jammed in there. Naturally, I didn't have any wrenches on me (left them in my panniers at home) and so I carried it home.

When I got home and got the bike on the stand, I really had to fight to get the rear wheel off. It's like it had forced itself into the dropouts or something. After some muscle, I managed to yank the wheel off and (forcefully) pull the chain out of the wheel. I remounted everything and noticed that the chain has some slack in it now. It used to be super tight. I also noticed a strange whirring and clicking noise coming from the rear wheel, so I cleaned the chain and re-lubed everything (thinking that it might be grit), but it's still doing it. Could I have jacked up my hub?

The wheel appears to be in true and I gave it a test ride. There is definitely some play in the cranks, that is, I pedal forward and there's a "dead spot" before I can feel the chain tension up. I can't hear the whirring and clicking while I ride, only when the bike is on the stand.

Sorry for writing a novel, I just don't know what I did to my bike and I'm a little concerned about it. Is it time for a new chain? A new rear hub? What's going on here.