The sell-off across the market is going to continue for at least another week, Wells Fargo said after the worst day for the Dow Jones Industrial Average and S&P 500 since February.

"We don't think the stock market pain is over just yet," Wells Fargo senior analyst Christopher Harvey said in a note.

Earnings reports from technology companies are "1-2 weeks away," which Wells Fargo said are "the next potential catalyst to pull the market out of its tailspin."

Thursday's trading session ended another 546 points lower a day after the Dow sank more than 800 points and the S&P 500 dropped more than 3 percent. It was also the 28th time since 2011 the S&P 500 posted a more than 2 percent decline, according to data from Birinyi Associates.

"If you can be patient and withstand some further pain, we think there will be better levels to de-risk or reposition for the future. That said, in the coming days, we do expect to see more market pain and forced sellers," Harvey said.

Wells Fargo recommended that clients add stocks that are buying back shares, as well as those with lower volatility. But the firm said it doesn't "believe investors should continue to aggressively de-risk or sell risk assets," as "the premium for risk aversion assets has increased sharply."