It could be that the drive is being indexed or something along that line. It's not normal, as none of the six computers I own running Win 10 do it. However, all of my computers have SSD boot drives which might be a factor.
If this is a new setup, it may be the Search Indexing processing reading and cataloging all the data on the drive. That said, it should eventually stop doing that. Idle, Windows should only need to access information in RAM, with the occasional read/write to the pagefile.
As crazyman noted, it would also be worthy to check the resource monitor to see what program is using disk resources.
Anytime I've had that happen, it's been either a failing drive or bloatware (perhaps even malware). It may be worth getting a rootkit checker, but again, do a bit of digging into what's using those resources.