Using this plugin will display current price indicator in Highstock.
yAxis: {
currentPriceIndicator: {
backgroundColor: '#000000',
borderColor: '#000000',
enabled: true,
lineColor: '#000000',
lineDashStyle: 'Solid',
lineOpacity: 0.8,
style: {
color: '#ffffff',
fontSize: '11px'
},
x: 0, //offset
y: 0, //offset
zIndex: 7
}
}
https://www.highcharts.com/products/plugin-registry/single/28/Current%20Price%20Indicator