Charles Schwab Chief Investment Strategist Liz Ann Sonders thinks we’ll see increased volatility in the stock market, but expects stocks to continue to grind higher from here. Sonders tells Yahoo! TechTicker that the “wall of worry” is still intact, and says a bear market in the bond markets could trigger a “melt-up” in the stock market. And, she says valuations remain modest for a low-inflation-rate period.