BackTest: candles is real ?

 
Hello, I have a doubt about the back test. I am checking my indicator that points out the candles, making a back test would merely truthfully or I could find a chart with candles position that does not match up with reality?

Another doubt, if you increase the speed of the back test execution, eventually you find may be distorted?

thank you all
 

The history prices are from your broker. If you dont trust your broker's data, find a btoker you can trust.

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