What was going on when I was born?

THE Upper East Side is hardly known as a theater district. Yet it contains a surprising number of theaters, surprising even to the theaters themselves. Many of them have been East Siders for nearly a decade or more. But few are close neighbors. Many are tucked away on residential streets. And all have heard audience members say: ''You know, I live just a few blocks away and I didn't know until now that you were here.'' So now, nine of the houses have banded together, as the Eastside Theaters, to improve their visibility. As a curtain raiser in the campaign, they are conducting a festival (through Feb. 17) that offers a bargain in these days of astronomical ticket prices. For a $25 pass, one can visit all the theaters, choosing from more than 45 performances of 15 events including drama, a musical, comedy improvisation and operettas. That, they say, is a savings of $100. The pass is available at all the theaters. Tickets for individual shows range from $8 to $18.

Four state security policemen were convicted and sentenced to prison today for their role in the abduction and murder of a pro- Solidarity priest. The 25-day trial was believed to be the first in which a Communist Government had publicly prosecuted members of its internal security forces for the slaying of a dissident. The five-judge tribunal sentenced two senior defendants, both police supervisors, to terms of 25 years, the longest prison sentence under Polish law; the two lower-ranking men received 15 and 14 years. In accordance with Polish law, the judges determined guilt and levied punishment.

A headline in some editions of Sports Pages yesterday incorrectly reported the result of the basketball game between Arkansas and Southern Methodist. Arkansas won, 69-66.

Business leaders said the President's budget should have done more to narrow the deficit. Page D1. WASHINGTON, Feb. 7 - Senate Republican leaders said today that they would propose a one-year elimination of the cost-of-living increase for Social Security pensioners as part of a package aimed at reducing Government spending by at least $50 billion in 1986. The Senate majority leader, Bob Dole of Kansas, stressed that the Republicans would support the elimination, beginning next January, only as part of a larger package that included cuts in other domestic programs and in the military budget. Meanwhile, Republican and Democratic members of the Senate Budget Committee bluntly told Defense Secretary Caspar W. Weinberger that he should expect President Reagan's military budget request to be reduced.

''THE AGE OF CARAVAGGIO'' at the Metropolitan Museum of Art is on every count a most remarkable achievement. It has great paintings. It has paintings which, though not so great, have something irreplaceable to tell us. It has a schema, an argument and an armature. It brings instruction, it brings delight, and it also brings a terror that is all too topical. What more can we ask? It is the particularity of Caravaggio that within a period of 15 years or less - from 1595 to his death in 1610 - he turned painting around. There was painting before him, and painting after him, and no one can confuse the two. He brought to painting a new dynamic, a new and terrible ferocity of representation, and a readiness to face areas of the psyche that had previously been off limits. He did this primarily in Rome, then the unquestioned center of the international art world, but he also did it in Sicily, and in Malta, at a time when he was on the run from justice.

I T'S possible to get around town on subways and buses, rather than taxis and limousines, and to keep warm in down rather than fur. It's also possible for anyone on a limited income to go to the theater without mortgaging the house or living on pizza. It's not always convenient, because moderately priced shows are often far from Broadway. It's not always comfortable, because your choices may be standing room or a hike up more stairs than you thought possible to the kind of seat that makes you wish you were better padded. And, at the Theater Development Fund's booths, where half-price tickets are available on the day of the show, it requires patience and fortitude to face lines that can stretch down the block and double or triple back.

The BankAmerica Corporation announced yesterday that it had substantially increased its loan-loss reserve for the fourth quarter, cutting its earnings by $29 million. The move was taken to account for losses the bank may record in connection with its role as an agent for mortgage- backed securities that apparently were sold fraudulently. The California bank holding company said the revision was the result of an extra $58 million placed in its loan-loss reserve. That was added to the original reserve of $37 million, bringing the special reserve to $95 million.

The Phillips Petroleum Company, bowing to widespread Wall Street grumbling, sweetened the value of its multibillion-dollar recapitalization program yesterday. But traders reacted only mildly to the improved provisions: a $3.32 dividend to be paid in preferred stock and an offer to buy 20 million shares at $50 apiece. Wall Street professionals valued the new package at $47 to $51 a share, only slightly higher than their estimated value for the original package. Meanwhile, Carl C. Icahn, the New York financier, is said to be considering a new proposal to present to Phillips to buy at least 30 percent of the company at around $57 a share - $2 more than his earlier $55 offer.

For years, Rutgers, the State University of New Jersey, has been overshadowed by its Ivy League neighbors of the East and the great state universities of the Middle West and the West Coast. But over the last five years, a series of changes at Rutgers and in the State Legislature have put the school on the road to national standing as a center for research and learning, according to educators in the state and Rutgers officials and faculty members. ''Rutgers is in the middle of a significant transition,'' said T. Edward Hollander, the state's Chancellor of Higher Education. ''It is moving from the second tier of universities to the first. It's not there yet, but it will be.''

The Pabst Brewing Company directors would support an offer by the S&P Company for all Pabst stock at $10 a share - about $64 million - but probably will be precluded from doing so, the Milwaukee- based brewery's president and chief executive said today. William F. Smith Jr. said in a statement that Pabst was therefore officially taking a neutral position on the offer by S&P, headed by Paul Kalmanovitz, a California brewer. Mr. Smith said Pabst might be precluded from formally approving the S&P offer under terms of an agreement with the G. Heileman Brewing Company of La Crosse, Wis.

The sequel to the agonizing process of filling out Federal income tax returns is the agonizing process of filling out state and local tax returns. Some taxpayers will find the task less burdensome this year, but others will have new burdens. One in five New York taxpayers, for instance, will be able to limit the state and city tax filing ordeal to only five minutes, thanks to a new simplified form - the first new one since 1919. And those who live in New York City will find their tax burdens eased somewhat by a reduction in the city income tax surcharge. But those who work or live in Yonkers will discover they are subject to a new tax.

FRIDAY, FEBRUARY 8, 1985 International Four Polish officers were convicted and sentenced to prison for their role in the abduction and slaying of a pro- Solidarity priest. The 25-day trial was believed to be the first in which a Communist country has publicly prosecuted members of its internal security forces for murdering a dissident. A five-judge tribunal sentenced the four men to terms ranging from 14 to 25 years. (Page A1, Column 1.) Moscow's desire for U.S. computers is expected to be satisfied by new, more liberal high-technology trade regulations adopted by Washington and its allies. Industry sources say Soviet officials have begun negotiations to buy large numbers of Western-made personal computers, apparently for Soviet scientific institutes and schools. (A1:2.)