Debt collectors are starting to hound people who lost their homes to foreclosures or short sales over their second mortgages. In California, a foreclosure generally wipes out the borrowers’ obligation on the main mortgage but not necessarily on other home loans. “We’ve seen a lot of folks coming to us, saying, ‘I was foreclosed on, now these people say I owe $150,000 for my second loan; I thought everything was going to go away, what do I do now?’ ” said Noah Zinner, an attorney with Housing & Economic Rights Advocates in Oakland. Some experts think the trend will accelerate, causing foreclosure pain to linger.