A steady rise in crude oil prices and maintenance at the nation’s refineries means steady pain at the pump for U.S. motorists, motor club AAA reports. AAA lists a national average price for a gallon of regular unleaded gasoline at $2.39, up slightly from Monday for nearly a two-week streak of gains. By the motor club’s estimates, the national average for the price of gas is up more than 4 percent, or about 10 cents per gallon, from one month ago. “Pump prices in 48 states and Washington D.C. have moved higher over the last week, led by the switch over to more expensive summer-blend gasoline and increased driving demand,” AAA explained in a weekly retail market report . […]