Are you actually chopping or using a chain saw?
I cut it up into short logs using a reciprocating saw with a big blade. As a rather lightly-built woman I find it impossible to start a chain saw even though I’m in good shape. Then I chop each log with a spike and a ten-pound maul. I like the spike-and-maul technique better than using an ax because if I get tired and lose control of the tool I won’t cut my leg.