As a young programmer with the exact same problem, I'd like to point out that, while liking your job and other 'feel good' advices have their purpose, this set of symptoms could be caused by a deeper and very physiological problem. Short version: your brain might temporarily shut down and restart because all is not right with your biology. The worst thing about this scenario is that you'd also be heading towards chronic exhaustion, a nasty thing which takes years to recover from.

A checklist:

• do you happen to have low blood pressure? While not mandatory, this tends to aggravate everything below.
• do you work out? Not neccessarily fancy stuff, but reserving 15-20 minutes in the evening for school-style calisthenics might make a very notable change. I started seeing an improvement in the first week.
• how much do you sleep? Is your sleep schedule regular?
• do you eat well, in the farmacological sense? Vitamins and minerals especially.

[EDIT] Lastly, like JB King said, see if it happens with other tasks. Because if it does, it's almost certainly a physiological and not psychological problem. And physiological problems are solved through physiological means.

I bought a consumer-grade EEG recently and from just a few hours of playing around with it I'm pretty confident in its ability to detect how focused I am. I was planning to write some software to alert me and snap me back to reality when my concentration decreases and my mind starts to wander... but perhaps you should beat me to it :-)

Consider seeing a psychiatrist for a possible ADHD diagnosis.

I'm 29 years old, and I was diagnosed with ADHD about a month ago. I've found I've been a lot happier about things since my diagnosis.

Now a few initial caveats:

• There's the controversy about whether ADHD is even a thing/or is overdiagnosed to simply anybody who has trouble focusing.
• There's also the Barnum effect or confirmation bias - where if you can list some symptons and they resonate with, because they resonate with everyone.

But that said - given that :

• You said you've always been that way.
• It sounds like you've been trying hard to focus and feeling frustrated by it.

it sounds like it might be ADHD.

If you're still having trouble, do yourself a favour and get yourself referred.

Have you verified this with different kinds of tasks? For example, if something seems to require a lot of physical work but isn't very taxing mentally, how much stamina do you have to do this? Similarly, if something is mostly working in abstract thought and has little physical work how do you do in this case? I'd be tempted to collect some more data to see if this applies all kinds of tasks or if there are some that are worse than others.

Have you considered the idea of trying to find your strengths and see how this could be useful here? For example, have you considered cases where your curiosity could be an asset rather than a liability? Just an idea to toss out there.

Something to consider is that you did write a rather concise question on here so you are capable of doing some things at least.

I think everyone struggles with this.

Aside from the standard advice of getting enough exercise, having a good work environment free of distraction, etc, one thing that really helps is to break your work into smaller and smaller tasks. Each day, write a list of everything you want to accomplish. For each of those tasks, break it down into concrete steps you need to accomplish the goal. Each task should only take 5-10 minutes.

As you are working on the task (ex: "debugging a function") narrate in your head what you are doing. "Getting the records from the database, looping through the record set, fixing a bad reference, etc". By putting your thought process into words, you are keeping your brain from getting distracted. If you run into a roadblock, you probably need to break your tasks into smaller steps.

Of course, it’s impossible to keep this kind of pace up for 8 hours in the day. It’s important for any programmer to take is to step back and think about the big picture. Go for a walk. Think about how you can simplify your tasks. Think about how algorithms or data sets can be abstracted into cleaner structures. This is where you can let your brain wander.

Maintaining discipline, focus and motivation is probably one of the biggest challenges for people who do "brain-work".

This may be a great problem if not controlled at time.

I think there is one question you have to ask yourself: are you happy with what you do at work? If you aren't, then that will be a reason for distractions.

Even if you are really happy, or at least working as a software developer isn't that bad to you, you may have work related problems:

• Bad working environment.
• Annoying people working with or around you.
• Your working hours are hard to fulfill.

Another important possible factor may be bad diet. Have you changed remarkably your diet or food habits?

I suggest using paradoxical intention. In this case, instead of making effort to concentrate, make an effort to get bored. Then as you are now having troubles to concentrate, you will have troubles getting bored, and then you won't get distracted.

I'm also a software developer that happened to be bored when I'm programming or doing computer related work. But how can you be bored doing what you like?, and because of that question I couldn't realize I was bored, I didn't want to believe it. But the only time that I feel like trying to concentrate in front of the computer, is when I am alone in my car, waiting for the traffic to move.

Now I know that works, I understand why people that is not as interested as I in the job, got more things done, and of course concentrate easier.

To know more about paradoxical intention, I recommend the book Man Search for a Meaning by Viktor Frankl.