Workout App Pausing Randomly

I have the Apple Watch 6. I walk daily and use the workout app each time. It has started to pause randomly. Sometimes I’ll check along the way and it’s working fine only to get home to find it had paused itself later on. I’ve also noticed that I randomly have to put in my passcode to unlock the watch though I haven’t locked it and I’ve had it in throughout the day.

I do not have a tattoo under the watch and have checked my settings. Please help. I’m losing half of my distance!