I have now been running for almost 18 months and am very comfortable (if slow) at a 5k distance. By comfortable I mean I can run it all, can vary my pace within it, am not excessively out of breath, and don't many aches afterwards. However, I don't really feel I am progressing. My overall times at 5K remain much the same, and I run out of energy in my legs if I run more than about 7K. I would like to be able to run a longer distance occasionally, and I would like to be quicker at 5K. I should probably also mention I am almost 60 and hadn't run before I did C25K last year.
The runs seem to go better if I only run twice a week rather than 3 times a week (I also swim twice a week and do other active things). If I run twice a week, I usually do parkrun plus some sort of interval run (to try to work on pace). If I run 3 times in a week I often add in a longer run/walk style run to work on stamina.
Have others experienced this, and how have you broken through?