The US stock market pulled back from  its record heights  Monday, while oil prices jump with uncertainty about when oil tankers can resume crossing the Strait of Hormuz and restore the world’s flow of crude.  Escalations in the Middle East  are heightening tensions in the war with Iran and may be undermining a ceasefire. The Dow Jones Industrial Average was down 542 points, or 1.1%, in midday trading, and the Nasdaq composite was 0.4% lower. The S&P 500 also fell 0.5%, coming off its latest all-