Как на highcharts ось y сделать слева?
Задать opposite: true для yAxis.
Например:yAxis: [{
            opposite: true,
            title: {
                text: 'Test title'
            }
        }]
opposite: Boolean
Whether to display the axis on the opposite side of the normal. The normal is on the left side for vertical axes and bottom for horizontal, so the opposite sides will be right and top respectively. In Highstock 1.x, the Y axis was placed on the left side by default. Defaults to true.
api.highcharts.com/highstock#yAxis.opposite
P.S. Описание в документации какое-то невероятно мутное.