At the well-traveled intersection between Sam's Italian Sausages stand and the 4-H animal pens in the midst of the Lorain County Fair here, Rep. Donald J. Pease (D-Ohio) paused the other day to talk to two constituents. One, a local businesswoman, was complaining about government regulations. The other, a soil erosion expert, had an idea for a new one.

In the tiny Mississippi riverbank town of LeClaire, Iowa, store owner Otto Ewoldt told Rep. Jim Leach (R-Iowa) that high interest rates are driving him out of the hardware and small-appliance business.

Over in Cincinnati, Joseph E. Sumner, proprietor of the Busy Bee gourmet food shop, told Rep. Willis D. Gradison Jr. (R-Ohio) that business has never been better. "People aren't buying cars, so they're satisfying their appetites at home," he said.

If there is a message to Congress from the nation's heartland as it returns from its summer recess, it comes in muted, often ambiguous and sometimes contradictory signals: a host of festering anxieties amid a general sense of well-being, without an overriding issue, cause or personality to rally the concern.

If members of the House and Senate sometimes appear to be marching to 535 different drummers, it may be because these are the sounds they are hearing.

Rep. Richard A. Gephardt (D-Mo.) put it this way as he traveled with a reporter through his diverse but largely middle-class St. Louis district:

"There's a continuing sour feeling about institutions in general and government in particular, a sense that the economy isn't working as well as it should, that we're not as competitive and productive as we were, a kind of nagging frustration . . . But people are basically still optimistic and high on the country. Sometimes in Washington we talk ourselves into thinking things are worse than they really are."

"When people don't grab me by the lapels, it tells me something about the intensity of the issues," said Pease, whose district embraces unionized auto and steel workers, Cleveland and Akron suburbanites, farmers and, as he notes proudly, 55 different ethnic groups.

After a four-day swing through these fairly typical four Midwestern congressional districts late last month, a reporter opens a notebook filled with a mosaic of contrasting impressions and thoughts -- a blend of pastels rather than sharp, clear colors.

If many people are hurting from inflation, others are doing quite well. Most cope by cutting nonessentials, and some speak proudly of their belt-tightening efforts and ingenuity. Farmers are prospering, there are more and more two-income families, auto workers are protected by cost-of-living increases, and even retirees, especially those with ethnic or family traditions of frugality, have found ways to adjust.

The impending recession still is largely something that people read about in newspapers. They complain they are being taxed to death but are not clamoring for a federal tax cut.

Nearly everyone brings up energy, expressing more concern over cost than supply. They want action now but offer few solutions of their own (the exception being farmers' enthusiasm for grain-distilled gasohol) and do not appear overly optimistic that Washington will come up with any either.

One of the busiest spots at the Lorain County Fair, for instance, was the United Auto Workers' booth, where people lined up to sign pre-addressed postcards to Congress and the White House demanding an end to "oil ripoffs." But few paused to read or discuss the fine print of the union's specific proposals.

There's a lot of grumbling out there about a lot of things, but people tend to smile or blink uncomprehendingly when asked if, as President Carter asserted in his July energy address, they are suffering from a "malaise" or a "crisis of confidence."

"It's more of a frustration and an indifference toward political and governmental," said Leach as he drove through the lush cornfields of his southeastern Iowa district.

On the other hand, Carter may be right when he suggests that the countryside doesn't tremble when Washington goes through one of its political spasms, like the recent Cabinet shakeup.

People talk more of family, neighborhood and community problems -- probably as they always have, except in times of national crisis or high political drama.

At a Caterpillar engine retooling plant outside of Davenport, Iowa, Leach got more questions about the need for a traffic light in front of the plant than anything else, with opposition to gun controls and support for a state dove-hunting season running close behind. Pease caught some fallout from an impending school busing order in Cleveland, which is not far from the eastern edge of his district.

But even some of these parochial questions often touch on broader issues, tapping deeper concerns. In complaining to Pease about a federal judge's busing order for Cleveland, Ken Roth, a United Airlines ramp worker, talked extensively and emotionally about what he sees as overpreaching government, "a snowball that keeps getting away from us," as he called it.

In St. Louis, Margaret Ferguson told Gephardt why she dissuaded her husband, who travels in his work and has back problems, from buying a small, fuel-efficient car. "If people in Washington don't ride around in little bitty cars, why should he ride in one and spend his whole weekend at the doctor's?" she asked.

If the issue of payroll tax increases to finance the Social Security system is any barometer, people appear more concerned over the future than the present.

Several of the congressmen raised with their constituents the issue of continuing Social Security tax increases, including a big rate increase scheduled for 1981 that some lawmakers are talking of rolling back. Rather than railing at the taxes, even the younger workers who are bearing the burden of the cost expressed more concern about keeping the system alive.

"The fear is that there won't be anything left by the time you need it," UAW Local 215 President Bob Hopping told Leach during an encounter at the Caterpillar plant. "I feel by the time I retire there may not even be a Social Security [system]," said Ferguson, who worked for years in an office before quitting to be a fulltime housewife.

Sometimes it is difficult to tell the difference between what people feel from their personal experience and what they perceive from the news media as the dominant problems of the day. Several people, while talking in normal colloquial terms about their own experiences, lapsed into journalistic jargon (like "curbing inflation") when talking about national issues. Many also described national problems -- or other people's problems -- as more severe than their own. "They're so bombarded with bad news about what's going on that it's hard to be upbeat about it," said Gephardt.

Yet many in the Midwest reacted more emotionally than official Washington to news that the United States is selling refined heating oil and kerosene to Iran. "Has everyone gone mad? How stupid can they get?" thundered a well-dressed man after reading a news story on the oil sale at a cafeteria breakfast table in Davenport, slapping the newspaper accidentally into his scrambled eggs.

From Pease's district on Lake Erie to Gephardt's at the confluence of the Mississippi and Missouri rivers, hardly anyone could be found who claims to believe that Carter is doing a good job as president. But many praised his personal character, gave him credit for trying and blamed others, including his own party and Congress, for his failures.

Gephardt said that overriding all the criticism of Carter's actions and his leadership abilities is a "reservoir of feeling for him as a human being" that could pull him through the next election. Leach, although he finds Carter to be "a strange, unsettling man in a world that cries out for stability," also thinks he has at least an incumbent's edge.

But for Charlton Noble, a young black high school graduate in search of a job in St. Louis, the performance of Carter and the country's political and economic systems boil down to one thing: no job.

"First they say I have to have a high school degree to get a job and so I get one," he told Gephardt in the living room of his mother Alice, who holds down two cleaning jobs to help support her six children still living at home. "Now they say I have to have a year of college just to be a camp counselor. Carter, he promised jobs, but where are they? . . . I'm a high school graduate, but I'm wiped out."