Widespread shortages and production snags are driving prices higher for many everyday items, as an uneven economic reopening leaves Americans facing the unfamiliar risk of inflation. Significant price increases have affected used cars, medical care, appliances, energy, food and cigarettes in recent months, according to government data. Gas prices headed higher on Monday — before ending the day almost unchanged — after a cyberattack forced the closure of the nation’s largest fuel pipeline. Most economists expect prices for many goods and services to show continued gains on Wednesday when the Labor Department releases its next monthly inflation report. The Federal Reserve insists that today’s rising prices — up 2.6 percent over the past 12 months — will not blossom into anything like the economy-wide, double-digit inflationary spiral of the 1970s.