Linda Schultz of Macon, Ga., said she didn't mean to keep the president on hold, but she was working, after all. Schultz, a sales manager at Macy's department store, picked up the phone earlier this week after the caller refused to leave a message, and discovered a White House operator on the other end of the line.

Schultz's father, Raymond, is vice president of Sister Cities International, which is celebrating its 30th anniversary, and he recently met with President Reagan to discuss planned visits to China and other countries. Linda Schultz sent a letter to Washington along with her father, praising his 15 years of participation in the program and urging the president to continue promoting it. The letter prompted Reagan to call.

Schultz describes herself as a "liberal, radical Democrat," but she said she was impressed that Reagan took the time to call. "He respected what I had to say," she said. "He had a busy schedule, but he took 15 minutes out of it to talk to me." Well, almost. The White House reportedly clocked the conversation at 13 minutes. Remembering David, the 'Bubble Boy'

The Smithsonian's Museum of American History has acquired artifacts and memorabilia documenting the widely publicized life of David, the boy who was born with severe combined immune deficiency (SCID), leaving him defenseless against disease and confining him to a sterile, bubble-like environment for nearly all 12 years of his life. David, whose last name has not been released to protect the privacy of his family, was the subject of a television movie. He died in February 1984.

The recently acquired objects include a mobile support vehicle, a space suit, bubble-shaped isolation units and personal objects such as games and drawings. The donated objects are an addition to the museum's Medical Sciences Division. A museum spokesman said the materials will be available to researchers and scholars, but that there are no immediate plans for an exhibition of them. Carrying the Light of Peace

Soviet schoolgirl Katerina Lycheva began a 12-day tour of the United States yesterday, reportedly causing a stir when she arrived at Chicago's O'Hare International Airport. Following a breakfast with two dozen elementary school students, Lycheva, 11, lit a candle and said, "If everyone who wants peace lit a candle . . . there would be no dark spots left."

The fifth-grader from Moscow will continue on to Washington, New York, Los Angeles and Houston, meeting public officials and talking to schoolchildren about peace. Her trip is sponsored by the San Francisco-based organization, Children as the Peacemakers Foundation. Virginia Garrison, a foundation spokeswoman, said the organization requested a meeting with the president and his wife but was told they would not be in Washington at the time of Lycheva's visit. End Notes

History will be made today at the National Gallery, according to spokesman Neill Heath, when anticipated crowds visiting the "Treasure Houses of Britain" exhibit break the attendance record set in 1977 by the "Treasures of Tutankhamen." According to Heath, 832,000 had visited the treasure houses exhibit as of yesterday afternoon. With an average rate of 700 viewers an hour, the show should have no difficulty exceeding the previous record of 835,000 visitors. The show continues through April 13 . . .

Clint Eastwood's bid to be mayor of Carmel, Calif., has inspired a new rock song titled "Don't Mess With the Mayor." The tune, recorded by a local pop group called the Medflys, has brought "a ton" of phone calls to Carmel radio station KMBY, a spokesman said. Washingtonians should take note of the lyrics: "I guess it's only natural/ Look where Ronnie Reagan went/ I can see the T-shirt now/ Saying 'Clint for President!' "