It's getting easier. I'm a heavy guy, and a run typically leaves my calves feeling like they were assaulted with a hammer. I've only got 70mi on my shoes, and they're pretty comfy. So I think it's something to get used to.
I'm training for a half marathon. I put in 7mi today when Hal Higdons plan only called for 4. At first I was very proud. But now I'm just tired and nauseous hahaha.
My personal recommendation is to be careful with the training. Stay close to the recommendations. If you go much longer than asked for (especially in speed, but also in time/distance) you might be doing yourself an disservice. There's a certain growth curve for all the systems you're improving, and if you shoot past that you'll be objectively degrading other systems.