NEW YORK - Worried about that niggling pain in your arm? Concerned about those persistent headaches? If you’ve searched online for information about medical woes you’re not alone. The number of so-called cyberchondriacs seeking health information on the Web has soared to about 160 million in 2006 — a 37 percent rise over two years, according a new poll. “Cyberchondriacs now represent 84 percent of all online adults, up from last year’s 80 percent, and 72 percent in 2005,” Harris Interactive, the market research firm that conducted the survey, said in a statement.