The economy may be healing, but some, big banks are suffering from a housing hangover. JPMorgan Chase spent $3.2 billion last year to fight lawsuits, almost all of them over poorly written mortgages. That was down from $5.7 billion in 2010, but it made clear that housing still haunts the bank. The bank said that it set aside $528 million in the last three months of 2011 to fight lawsuits. It also spent $925 million in the fourth quarter to carry out foreclosures and handle mortgage defaults. “There’s still a huge drag,’’ chief executive Jamie Dimon said. The expenses took a bite out of JPMorgan’s quarterly profit, which fell 23 percent from $4.8 billion a year earlier, to $3.7 billion, or $1.12 per share, missing Wall Street expectations. Revenue fell 17 percent to $22.2 billion. It was the first time in four years that JPMorgan fell short of expectations.