Its not at all effecting my running...
It may not be affecting you now significantly, but it is probably doing something. Do like Josse said and get on it now before the little pain in your arch leads to a bigger pain in your ankle, then a muscle strain in your calf, then a pulled hamstring.., etc. Your body is tremendously connected in this way. Something is compensating for your arch so you don't feel it hurt when you run. Be sure to be careful and stop the little pain before it turns big.