How do the charts on MetaTrader 4 work?
The charts on MetaTrader 4 reflect the 'Bid' price only; the 'Ask' price is not shown on the charts.
You can, however, draw an 'Ask' line on the charts by clicking on the chart and selecting 'show ask line'. This will result in an estimation of the 'Ask' price, which is based entirely on the spread. You should bear this in mind when conducting any historical analysis using the charts available in MetaTrader 4.