Shares have soared 70% since the start of October.If you looked at the stock chart of SoFi Technologies (SOFI -2.31%), you wouldn't know if you were looking at the price movement of a real business or a drawing of a roller coaster ride. The company has taken shareholders on a wild journey in the past few years.SoFi currently trades 50% off its peak price, but it has experienced monster momentum in recent times, soaring 70% since the start of October (as of Nov. 8).But can this surging fintech stock be a mil ...