Ask HN: Thought tracking (fuzzy)

I'm quite confused about this problem so I'm just going to blurt out. I hope someone can make sense of it and help me. I find remembering everything I think of and about difficult. I spend much of my day thinking but I don't feel like I reap the rewards that I should. I forget what I was thinking about, I come to a conclusion on something but forget it or don't develop it, I don't develop my thoughts fully enough to explain them to people, I don't know when to stop. Can anyone suggest a strategy or framework for organising or tracking thoughts that doesn't require me writing / designing my own software? I think what I want is something that allows me to organise my thoughts into concepts or maybe thinking projects. I can add and evolve one over time adding the thoughts I have. I can discontinue one and put the reasons why it has been discontinued or fork it off into multiple thinking projects. I could write why I'm thinking about that thing and add the details of my life situation at the time so I know where I was emotionally when I was thinking those thoughts. You could also phrase this question as: are there any analysis techniques that I can apply to understanding life in general? I really want something I can use with just plain text files. Any ideas or guidance will be appreciated.