How to add vertical line to existing chart?

Please take a following attachment, mainly I just have 2 columns, strike price and OI. I used insert recommended chart, the clustered column chart is the one that looks best for me. I just wanted to dynamically add a vertical line to the chart with whatever the current price is (430.5). I tried to follow Mutiple examples online but my chart always look messed up after I try to add the vertical line. Any suggestions or help?