7-zip is now cross platform. There used to be a linux implementation called p7-zip but its not necessary any more.

As everyone else has said: kidney issue. If its an infection (you should definitely get this checked out), you’re going to need antibiotics. Drink a lot of water - like, a lot - and introduce cranberry juice to your drinking habits (won’t fix the infection but there’s some evidence its preventative).

If its a stone then get ready for the worst pain in the world but also drink a lot of water to help break it up/aid its passage through.

TL;DR - get a GP appointment and start drinking a fuck ton of water.