I had a run last week (around dark, muddy German woodland, randomly – mud, cobbles, tarmac). The day after, my left heel pad(?) was so sore i couldn’t put full weight on it. Bruised? I dunno. Gluwein in the german market later on helped.

Is this common? I don’t run much/at all but fancied it being bike less.

I’ve done that. Brutal isn’t it.

it’s a bit sore.

Reasonably common yes. You might want to try a gel pad under your heel if pain persists.

Thought I’d try running after fracturing wrist. Ended up with shin splints. Then wrist healed and didn’t bother running no more. Need to get the body accustomed.

https://breakingmuscle.com/running/a-week-by-week-guide-to-becoming-a-runner-later-in-life-and-or-safely

Try to let it heal up asap!, avoid putting any weight on it until the pain noticeably lessens.
Professional athletes with injury this get crutches and a massive padded boot at first.
It’s one of the worst injuries to try and shift if it persists.
I found not letting my heel hit the ground at first followed by using a doughnut shaped insert helped it to eventually clear up, it took a few months!

I also managed this and it hurt like **** for about 6 weeks. Really quite debilitating.

Try not heel striking and or building up to it.