About 14 million Americans have gained health coverage since Obamacare’s insurance expansion began in 2014 — but those new enrollees haven’t swamped the nation’s doctors’ offices, new research shows. When the health-care law started, there was concern that an influx of new patients could overwhelm doctors. It’s already hard enough to get an appointment with a primary care provider — wouldn’t millions of newly insured Americans just exacerbate the problem? More…