What was going on when I was born?

When securities analysts talk about the American Stock Exchange these days, they often recall the ''go-go'' years of the 1960's, when owners of hot stocks often saw their investments double or triple. That speculative boom fell apart in the early 1970's, and many investors felt that it would never return again. But in recent months the American Stock Exchange and the over-thecounter market have been the scene of vigorous trading action. While the New York Stock Exchange continues to churn in what has become characteristic fashion - lurching ahead one day and abruptly downward another - the broad price indexes in both the Amex and Nasdaq markets have been setting new peaks all year.

An optimistic mood permeated a meeting this past week of the world's leading bankers, who surveyed the economic situation with unusually good feelings. The problems of developing nations' debt and East-West relations were thoroughly discussed during the three-day meeting of the International Monetary Conference, but this time there was a clear sense that the problems were manageable. ''There's a feeling of 'hey, we might muddle through after all,' '' said Frederick Heldring, deputy chairman of the Philadelphia National Bank. Although substantial economic difficulties remain, the bankers noted that many of them - such as the oil-producing countries' balance-of-payments surpluses - have occurred before and have been resolved before.

Because of an editing error, an article in Metropolitan Report in some late editions Saturday incorrectly described the participation of the Democratic county leader of Manhattan, Herman D. Farrell Jr., at a meeting to endorse Mayor Koch for re-election. Mr. Farrell presided at the meeting and abstained on the vote.

THE old brown Labrador retriever was lying peacefully on the grass at Leon Spinks's hideaway training camp - very peacefully considering that her master was pulling porcupine quills from her face with a pair of pliers. It wasn't the first time she had bitten into a porcupine, a concerned Spinks said. ''That's why they call them dogs,'' replied the last universally recognized heavyweight champion of the world. ''Me, something hurts me the first time, I don't go back.'' For a while, it appeared he wouldn't be back. The first time around as champion was a painful experience. The man with the gap-toothed grin and the driving tickets had become a national joke, a running gag for comedians in need of material. He blew the title and he blew his first comeback and the jokes continued. The comedians didn't know he was crying himself to sleep. But Spinks is back, in prime time on national television, just as in 1978 when he won the title from Muhammad Ali and then lost it to Ali. On Friday night, he goes for sport's most prestigious individual title for the second time in only his 15th professional fight. All he has to do is beat the undefeated Larry Holmes in Detroit, Spinks's new hometown. Laugh all you want.

The Economy House Speaker Thomas P. O'Neill Jr. sharply criticized the Administration's new tax-relief plan and predicted the House would reject the revised proposals. But the Administration disputed this. James A. Baker 3d, White House chief of staff, predicted a House victory, saying, ''In the final analysis we will prevail.'' (Page A1.)

An emergency Arab League committee met in the Lebanese mountains today in an effort to get this battered country's heavily armed factions to agree on a plan to end the bloodletting. With the situation rapidly deteriorating after six years of offand-on warfare, rooted in in centuries-old blood feuds and modern great power struggles, there seemed almost insurmountable obstacles. ''Racing against time,'' was the way the Lebanese state radio described the Arab League effort, Neverthless, Bashir Gemayel, the tough young commander of the Maronite militiamen, sounded a mildly optimistic note tonight after meeting with committee members at the Presidential Palace at Baabda. 'A Fresh Opportunity' ''This meeting has given us a fresh opportunity to deal with the Lebanese crisis,'' Mr. Gemayel said. ''We went to present out point of view.''

The unexpected resignation last night of Jorge Diaz Serrano as head of Mexico's oil monopoly was the climax to a long and bitter campaign by both Cabinet ministers and outside critics who felt that the company, Petroleos Mexicanos, had become a state within a state. Mr. Diaz Serrano, who was replaced by Julio Rodolfo Moctezuma Cid, a former Finance Minister and long-time associate of President Jose Lopez Portillo, was apparently undermined by his own success. Mr. Diaz Serrano, a 60-year-old former private oil contractor whose post as director-general at Pemex was his first job in government, injected life into the country's lethargic oil bureacracy and, in little more than four years, supervised the tripling of oil production, a rapid ascent in exports and a tenfold rise in Mexico's proven hydrocarbon reserves, to 67 billion barrels. But, as a result, the Government became enormously dependent on oil revenues to maintain the current economic boom, and Mr. Diaz Serrano emerged as one of the country's most influential figures and one of a handful of possible candidates to become the next president.

"I think he has very, very selfish people around him, people only of the upper echelon of the wealth of this nation."

Landlords of rent-stabilized apartments in New York City yesterday proposed record monthly increases for the 290,000 apartments due for renewals in the 12-month period starting Oct. 1. The increases would be 16.5 percent for one-year leases, 24 percent for two years and 32 percent for three years. The proposals were afnounced by Sheldon C. Katz, chairman of the Rent Stabilization Association of New York City, which represents the owners of some 43,000 buildings, with nearly 900,000 rent-stabilized apartments. He asserted that a majority of tenants in rent-stabilized apartments paid $200 to $250 a month, compared with a citywide average that was probably closer to $300, although he acknowledged that apartments in certain parts of the city, particularly Manhattan, rented for far more.

New York State invested $85 million of retirement funds in residential mortgages this spring in an effort to assist the state's flagging home construction industry, and it plans to invest $200 million more this year, the state's Comptroller said yesterday. New York is the first state to use public pension funds to purchase home mortgages. Stimulating the building of ''sorely needed and affordable housing,'' will contribute ''to our state's economic well-being,'' said the Comptroller, Edward V. Regan, who is the sole trustee and investment officer for the Common Retirement Fund, which is the state's largest pension fund. Last October, a similar plan to use $250 million in New York City municipal pension funds to buy federally guaranteed mortgages was announced by City Comptroller Harrison J. Goldin. But none of that money has so far been invested in mortgages, and financial experts familiar with the plan said yesterday they were skeptical of its feasibility.

Brook trout no longer crack the glassy surface of Big Moose Lake here in the western Adirondacks. They have vanished, along with crayfish and frogs, loons, kingfishers and most of the swallows. The chirping tree frogs called peepers have largely disappeared or stilled their voices, and blights are killing the beech and yellow birch, spruce, tamarack and pin cherry trees. An unnaturally silent spring, worrisome to conservation officials and naturalists, has fallen over sectors of this wilderness, the rustic setting of Theodore Dreiser's ''An American Tragedy,'' a novel closely based on a murder on Big Moose Lake in 1906. Now, said Commissioner Robert A. Flacke of the New York State Department of Environmental Conservation, an environmental tragedy is unfolding in these high western parts of the largest park preserve outside Alaska. Pollutants borne by rain, wind and snow and traced to factory emissions from heavily industrialized parts of the Middle West have left more than 200 acid-pickled lakes devoid of fish and are disrupting the life chain in ways that scientists are striving to understand.

The first round of trade talks that the United States hopes will lead to resumption of Soviet grain purchases will begin tomorrow in London. Although the two-day conference has been described as a routine, twice-yearly discussion as prescribed by the current United States Soviet grain trade agreement, it will be the first high-level meeting with the Russians since the curtailment of sales to them was ended last April. Agriculture Secretary John R. Block said Friday that several matters could be discussed by the two trade teams. These could include American permission for immediate Russian purchases of wheat and corn from the 1980 crops, or a simple extension of the five-year grain trade agreement, under which the Soviet Union was committed to buying six million to eight million metric tons of American wheat and corn each year. This agreement expires Sept. 30.