In my story so far, in this chapter labeled "Longing", there are some time flips, where it begins in the present and then goes way into the past, the character is reliving a moment in his life, and then it flips back to his kid years. But it ends with the present again. Some of the people revising this bit found it both helpful to understand the character, but really confusing and couldn't keep up.
Is it too much to do this or is it fine to have it?
The thing about flash backs is you don't want to do it too often or all at once. You are basically doing an information dump onto the reader who is struggling to keep up as your readers have mentioned. Instead of doing it all in a chapter, spread it out. Find other parts of the story where you can have a moment to think back that will provide pertinent information to the scene. It's okay to provide background history to a character to better understand them, but what you want to avoid is basically doing what you are doing.
Keep the flashbacks relevant. In other words, don't do a jump back, then a jump forward slightly, then another jump back and then present time again. It's too much and providing too much information at once that distracts from the current plot. If the information we learn from the flashback is not directly needed by the current present scene, then the information is not needed at that moment.
It's just like writing an essay, you want to keep the focus on a specific topic or specific reference point. If the reader needs to know all the historical information by time the current point in present is happening, then build up the history to that point by spreading it out in the previous chapters.
Plus it helps keep the reader interested in finding out more with teasing them on segments of the past. If you give away too much of the history at once, it ruins the mystery of their character as well as takes away from the adventure of getting to know a character slowly over a book.
So in the end don't try to provide a history book (especially jumping around multiple time points at once). Spread it out and let the flashbacks build up over time so that you don't overwhelm the reader.
When you use flashbacks, be sure that it is clear to the reader that this is a flashback. I recall a book I read once that started in, let's call it the "present", and then there were several chapters that were one long flashback that. If the author said anything to indicate this was all flashback, I missed it, so I was assuming that chapter 2 and following happened after chapter 1 rather than before, and it got very confusing. In chapter 1 the author said this conflict was resolved, but now in chapter 4 it's still going on. Did it restart? Was the resolution from chapter 1 not complete? When I got to a point where I realized that a statement in a later chapter was what the speaker in chapter 1 was referring to when she said "I remember when ...", I finally realized that this was all a flashback.
My point being, as the author, yes, YOU know that event X happened 10 years ago while event Y happened yesterday. But is that clear to your reader, or are they losing track of what happened when with the flashbacks and flash forwards? In a good story, you want the reader to wonder what happens next. They shouldn't be wondering what is happening now.
I think a real danger you run into with this method is the 'man on a train scenario'. Remember that what your reader is immediately concerned with is what your character is doing now. Having him spend pages upon pages sitting on a train recalling his childhood might be extremely relevant, but to the reader it's still pages and pages of him being on a train and nothing really happening.
Trust your readers. It sounds like the flashback is necessary but maybe not set up well enough.
I've created some terrible flashbacks (and read a lot of other people's) and here are the two rules of thumb I've learned:
Be clear. When you jump in time, make it clear that you're doing it and where in time you're picking up. Usually something as simple as "The day before, ..." is enough.
Flashbacks within flashbacks should be avoided unless absolutely necessary and carefully constructed.
Have you read Holes (seeing the movie is fine too, as it's like the one movie that was 99.9% faithful to the book that I've ever seen).
The climax relies on understand three-four-five-six-seven (the one story is seen is mentioned as it's a passing event in another which only works by not knowing who you're reading about until it's conclusion, but the sixth and seventh ones I think are movie exclusive... it's been a while since I read the book, but the movie was doing flashbacks to begin with so why not. Another story is a flashback to the character hearing the story that we then flashback to... Basically, there are three real stories that are all true to some extent in the fictional setting and a lot of jumping around in to each of them) stories that all contribute to the final action and all take place.
To help break this up, all time periods are described in the book in seperate chapters (again, one is recalled by recalling hearing the story at an earlier point in time, but they make it clear). And are told in quasi-tandem (aside from the modern setting, no time period is featured back to back).
Basically, the storyies told are as follows:
So again, if you haven't read the book, its a great use of the Flashbacks and again, the one change between the book and the film was that the main character in the book is described as being overweight and later having noticably slimmed down as a result of his physical activites in the book... which is not a word used to describe the teenage Shia LeBouf who played the main character in the film (Shia LeBouf was commited to trying to put on the weight, but the books author personally stepped in and said it wasn't needed in the movie and even threated to rewrite the book so the character was slim to begin with in all iterations if LeBouf was going to continue to try and put on excess weight and then lose it fast during a point where his body was still changing and was likely to have some serious health complications). In the course of the story, this amounted to dropping about two or three lines and giving the character's nickname of Caveman a different origin story (in book, it was in part because of the character's size. In the film, it was because he found a fossil, which also happened to be an event in the book.).
