Since the main forum is of no help,

I keep throwing the chain on my bike. For 6 months never once did it come off, and now 3 times in 2 weeks, and several otheer times I've heard it catch on the cog. The chainline has always been about 3mm off. I swapped out the original cog that went on with the new chain and ring when I built it. I figure it is either the cog not matching well with the chain, or the 8 speed sram chain I have on now developing too much side to side flex.

Any ideas? I don't want to get a new cog only to find out that it might not be the problem.