Sounds like you need a process, rather than a tool. Personally, I jot down everything that gets mentioned to me on paper and, within 1-2 days, it will end up in the project management system (if it is something to be worked on). Once it's there, I strike it through in my notepad. So basically, 99% of my notepad is a scribble - only 1% that I need to think about remains un-struck.

That feels kinda familiar. My experience might or might not be helpful.

I read about Getting Things Done, and I worked to track everything in one place, but I find that task tracking in two places work best for me:

1. Something like Evernote or Simplenote, for capturing notes on any device that's handy: phone, tablet, computer, etc. Being able to search really easily is crucial, to avoid duplicate topics.

2. Something like Trello for easier prioritizing and categorization. Moving around the index card analogies is much easier than moving text.

Using email as an issue tracker is an anti-pattern. It means your work to prioritize can get casually jumbled, and for me, that flow can get interrupted more easily. Ditto for Slack.

I like paper notebooks - I used one at work so I wouldn't drop any of the tasks I was juggling - but they're less portable than my phone. Before that, I had a Hipster PDA (index cards and a paper clip - http://www.43folders.com/2004/09/03/introducing-the-hipster-... ) but I had lots of notes, and searching was awkward, meaning "just write it (again) before I forget it, sort it out later," meant there was curation involved, and that using 1. above was lower-friction and just overall better.

Paper notebooks are great since writing down tasks turns them into something real because of the haptic feedback from touching paper.

Note apps, task apps, etc. all can not handle to that considering the brain simply considers things with haptic feedback more memorable and actionable.

Strongly recommend

https://tiddlywiki.com/

Use it well and it'll serve as both a todo list and your own personal instantly searchable, super fast knowledge base.

I pipe emails, GitHub, etc into a private Slack channel, and use starred slack messages as my inbox.

Hubstaff takes screenshots while you work and you can jot down notes when you feel like it.

I also find myself reviewing my Chrome history sometimes if I have no idea all the things I had been working on all day.

Designing productivity tools is one of my favorite procrastination activities ;)

Personally, I use Trello with the Planyway addon.