STOP testing immediatly, you will destroy the UNO with the current meter connect that way.
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A current meter should be wired in series with the resistor, not in parallel. The way you have it connected, you could completely remove the resistor and still measure the same current. Essentially you are directly shorting pin 3 to ground, with only the internal resistance of the meter (which is very low) and the internal resistance of the output pin of the atmega328 limiting the current. If you are very, very lucky the atmega328 may still work, but I suspect pin 3 is damaged.