Jesse Eisenberg wrote, directed, and stars in “A Real Pain” but gave the showiest role to Kieran Culkin, who gives one of the best performances of the year.

Eisenberg, a careful writer with an excellent ear for what people say, and the spaces left by what they don’t say, gives the film a title with an illuminating double meaning. There’s the colloquial use for someone or something that is annoying, frustrating, but generally in a minor way. It is sometimes said with affection, sometimes with impatience, sometimes both. Then there is the more literal recognition of two words of enormous portent. This is a movie about pain, about generational pain caused by historic trauma and by internal, very individual struggles. It is about the pain we bear and the more difficult challenge of the pain we witness but cannot fix.

David (Eisenberg) and Benji (Culkin) Kaplan are close but very different first cousins who are on a Heritage Tour of Poland, a small group led by a British historian, visiting locations related to the Holocaust. They are planning to leave the tour a day early to stop at what was once the home of their late grandmother, a Holocaust survivor.

David is intentional and careful. He worries constantly, which makes it difficult for him to feel comfortable around new people. Benji is impulsive, with volatile moods and no filters. He is often annoying, but he is genuinely curious about other people and warmly sympathetic, and authentically vulnerable, which makes people feel comfortable, even protective.

As the trip begins, David leaves a series of voicemails for Benji with advice and encouragement and concern. Meanwhile, Benji is at the airport early, chilling (or maybe he just has nowhere else to be). The tour guide is James (Will Sharpe), who begins by telling the group he is not Jewish but very interested in the culture and history. The other people on the tour are Marcia (Jennifer Grey), a recent divorcee, a retired married couple, Diane (Liza Sadovy) and Mark (Daniel Oreskes), and Eloge (Kurt Egyiawan), a survivor of the genocide in Rwanda and convert to Judaism.

The inherent impossible conflicts of a trip like this (based on one Eisenberg and his wife took) are handled exceptionally well in the film, often explicitly. Benji objects to first class train travel en route to a tour of a concentration camp, compared to the horrific cattle car transport of the people the trip is attempting to honor. He’s right and he’s wrong, of course. Would walking to the site be more respectful? Is there any accommodation today’s visitors could make that would not be somehow disrespectful? In another moment, Benji tells James he is throwing too many facts and statistics at them. Again, he’s both right and wrong. While history is essential for understanding the past, it is impossible to find an appropriate context for paying the right (if there is such a thing) kind of respect to those who suffered and perished. There will always be survivor guilt, but anyone who thinks skipping dinner or traveling economy — or immersing themselves in numbers and names — will assuage that burden is in denial. And Benji, by the way, stalks out of the first class car with a superior edge, and then ends up traveling first class anyway, laughing at his pretension.

Benji wants a picture of himself doing a silly pose on a huge statue memorializing the Warsaw uprising, the largest armed Jewish rebellion against the Nazis, insensitive. David finds that insensitive and disrepectful. At first, the others in the group do, too, but then they join in, finding some release in pretending to be part of the heroic response to oppression. As James reminds them, this is just one example that refutes the claims that Jews were docile in response to the horrors of the Holocaust. So perhaps the silly pretense of fighting alongside the Jews confined to the Warsaw ghetto eased the tension and helped the group bond.

The challenge of comfortable 21st century American tourists visiting sites from the Holocaust in a manner that is meaningful is juxtaposed with the very personal conflicts between David and Benji. Both struggle with anxiety. David takes medication, does meditation, and has established a satisfying life with a wife and son (played by Eisenberg’s real-life son, Banner). He has a job, though it is one Benji thinks is useless. And he worries about Benji. Their grandmother, who died a few months earlier, left money for the two of them to visit her home in Poland. Benji has been rudderless, without a job or family, self-medicating with weed. David hopes that bringing Benji on the trip will help him get some distance from his grief and give him something to do.

When David’s patience runs out, Eisenberg delivers a beautiful speech to the rest of the group about his love, frustration, worry, and his envy for Benji’s easy ability to connect and endear himself to everyone he meets. Like Norman Maclean in the book and movie “A River Runs Through It,” Eisenberg recognizes that:

We can seldom help those closest to us. Either we don’t know what part of ourselves to give or, more often than not, the part we have to give is not wanted. And so it is those we live with and should know who elude us. But we can still love them – we can love completely without complete understanding.

Parents should know that this movie has mature material including historical references to the Holocaust, very strong language, smoking, drinking, and drugs. The characters discuss a sad death and a suicide attempt.

Family discussion: Who from this group would you rather travel with? How can we best show respect for the past?

If you like this, try: the “Trip” trilogy starring Rob Brydon and Steve Coogan