while we're on the subject, i didn't want to create a new thread
i'm also very new to fixed-gears and riding in general,

but i was riding the other night and i heard a pretty loud, unsettling noise come from the hub, and my chain fell off and my pedals became disengaged, and from what i can tell, my sprocket came loose, and the rear wheel shifted forward, causing my chain to fall off.

i was just wondering how normal this is. can i just tighten it back by hand, and check it every once inawhile? or is a repair needed.