For years, older workers have been warned to prepare for rising healthcare costs in retirement. But the latest projections on medical care paint a pretty bleak picture for seniors who plan to get the majority of their retirement income from Social Security.In a new report from HealthView Services, a provider of cost projection software, healthcare costs in retirement are rising twice as fast as the typical annual increase in Social Security benefits -- so much so that over time, retiree healthcare costs are likely to exceed what they collect in Social Security.