What was going on when I was born?

Enforcement of comprehensive immigration legislation in Congress would present a huge challenge to the already overburdened Immigration and Naturalization Service, according to many specialists in the field. Alan C. Nelson, the Commissioner of Immigration and Naturalization, said the agency was prepared to enforce provisions of the legislation, approved in different forms by both houses of Congress, forbidding employment of illegal aliens. Few people outside the agency expressed such confidence, although several immigration lawyers said management of the agency had improved noticeably under Mr. Nelson's leadership. Volume of Work Cited Sam Bernsen, a lawyer who worked at the immigration agency for 35 years in various capacities, including general counsel and Assistant Commissioner, said: ''The Immigration and Naturalization Service is hardly able to carry out its responsibilities under present law. This legislation would lead to a mammoth, unprecedented increase in the volume of work. I do not think I.N.S. is up to the challenge with the present level of manpower. A token increase in manpower would not make it possible to do the job.''

''I get scared and stuff because what if they do something to me.

The House-Senate compromise tax bill is a patchwork of measures intended to raise $50 billion in revenues over four years while leaving individuals relatively unscathed. This deficit-reduction effort is expected to go before both chambers of Congress this week for final approval. Congressional tax writers were able to avoid imposing a general tax increase on individuals during this election year. They did so by scouring the tax code and chipping away at many business and investment tax breaks and delaying or repealing a number of benefits for individuals that have not yet gone into effect.

Forget that Dwight Stones broke an American record by high jumping 7 feet 8 inches. Forget that Steve Scott and Sydney Maree made the United States Olympic team, even though Jim Spivey beat both in the men's 1,500-meter final. The impossible happened tonight as the nine-day United States Olympic track-and-field trials ended at the Los Angeles Memorial Coliseum. Mary Decker lost.

A group of prominent Roman Catholic theologians from Europe, Latin America and the United States issued a statement yesterday that defends recent theological movements that call for church involvement in politics, especially in the third world. The statement from the theologians also protested efforts on the part of high church officials to criticize and blunt these movements, known collectively as the ''theology of liberation,'' by discrediting their spokesmen. Though the officials are not named, a thinly veiled allusion to Joseph Cardinal Ratzinger, the Vatican Cardinal in charge of doctrine, appears in the text. The Cardinal's views usually reflect those of Pope John Paul II, who has often addressed the themes that are central to the movement, sometimes criticizing aspects that he considers too political.

The Economy Machine-tool orders soared 27 percent in May from April and 137 percent above the depressed level of a year ago. But industry leaders still see a need for more improvement to fully restore profitability. (Page D1.)

Legal representation for abused and delinquent children in New York State is often inadequate and falls short in many cases of meeting state and Federal laws, an inquiry conducted by the New York State Bar Association has found. The investigation, which covered the period from 1980 to 1982, was the first comprehensive examination of the so- called law-guardian system, which represents 80,000 children a year in the state. The program, which was established 22 years ago, costs the state $10 million a year. A report issued by the bar group said legal representation in almost half of all cases studied was found to be either ''seriously inadequate or marginally adequate.'' In fewer than a third of the cases studied was representation found to be ''effective'' or ''acceptable.''

The sour stench of garbage and alcohol rose from the sidewalk in hot waves. In front of the Carter Hotel on West 43d Street, there were children everywhere, hanging off the door of the Rose Saigon restaurant, swinging on fire hydrants, wrestling in piles of beer cans in paper bags. Angel, 4 years old, played with an empty Bacardi rum bottle. Ann, 6, mimicked a common sight on the street, pursing her lips and sucking in, as though dragging on a marijuana cigarette. Michael, 9, held on to his baby sister's carriage and watched wide-eyed as police officers led away a handcuffed woman, in a purple jumpsuit, screaming obscenities. They are the children of Times Square. They grow up quickly in theneighborhood of drifters and derelicts, where sex and drugs are bought and sold on every grimy corner and violence and pornography and exploitation are the traditional values. They see things every day that other children only see through the glossy filter of television.

Fifty years ago Mayor Fiorello H. La Guardia shepherded into existence in New York City the first public housing authority in the United States. Its mandate, as he described it a year later at the opening of the first project, was ''to give the people of my city, in place of their tenements, decent, modern cheerful housing, with a window in every room and a bit of sunshine in every window.'' Last Thursday, Desiree Bomman, who had been living with her 3-year-old daughter, Shun-Ning, in a cramped basement apartment in St. Albans, Queens, received word that Apartment 5H at 135-06 24th Street in the Ravenswood public housing project in Astoria, Queens, was available to her. Her new living room is 15 by 17 feet. The stove and refrigerator in the kitchen gleam. The wide casement windows in the one-bedroom apartment look out at the tops of 50-foot-high maple trees. The rent is 30 percent of Miss Bomman's income, or $209 a month.

Orders for machine tools jumped 27 percent in May from April as the industry continued its month-by-month strengthening, the National Machine Tool Builders Association reported yesterday. The gain followed a 23 percent rise in April. ''It's encouraging that the industry is starting to build a backlog,'' said Christine Chien, an analyst at Prudential-Bache Securities Inc. ''We're seeing a sequential improvement on a monthly basis.''

Japan's love of electronic gadgets is producing an unwanted and potentially lethal side effect - battery pollution. Mercury, a toxic metal used in most batteries, is starting to seep into the soil around garbage dumps. The leakage has raised fears that Japan is slowly being contaminated by the dry cells that power its calculators, cameras, portable stereos and watches. Although no ill health effects have been reported so far, the situation is receiving special attention here. In part, that is because the electronics industry is so important to Japan. But it is also because people here are haunted by the Minamata tragedy, the worst mercury poisoning incident in history. During the 1950's and 1960's, hundreds of people were paralyzed, crippled and killed from eating fish contaminated by mercury wastes discharged by a chemical plant into Minamata Bay in southern Japan.

Scofflaws could learn to hate Sidney. That's because Sidney - the Summons Issuing Device for New York - can remember 10,000 license plates at a time and alert a traffic agent right away if the vehicle at hand has a shady past. City officials believe that Sidney, a handheld computer, will be ''a very powerful tool'' against scofflaws who now think they can ignore summonses with impunity. So the city's Transportation Department plans to ask the Board of Estimate this week for approval of a five-year, $22 million contract to begin producing the devices.