Stock prices have been soaring, but many investors are worried about the future.The S&P 500 (^GSPC -1.60%) has been breaking records over the last few weeks, officially reaching a new all-time high in July. As of this writing on Aug. 1, it's up by about 25% from its low point in April.However, not everyone is optimistic about the market right now. In fact, one-third of U.S. investors say they are feeling "bearish" about where stocks will be in the next six months, according to the most recent weekly survey ...