5k is still hard to run 6 months later

I’m not understanding why i still have such a hard time with 5k’s i run them at least 3 days a week. I have completed 2 10k’s since starting my running journey. I want to be able to run with some sort of ease. But even a mile sometimes is hard! When will it get easier?

Edit: i would just like to thank this amazing community! You guys did not only answer my question but provided valuable information. I’m excited to see how zone 2 running improves my distance!