Computer doing frequent freezes
My MP 5,1 10.13.6 w/dual monitors has been freezing a number of times recently. In Safari or Pages I will click on something and just get a spinning technicolor wheel. It will last maybe 30 sec to 1 min. I have not timed any intervals. Sometimes I am unable to do anything. I am unable to click on a button in any other app. I frequently have 3 to 5 apps active. Other times I can move the cursor to another app and have control but not on the frozen app. I opened Activity monitor and found that sometimes it reports that Pages or Safari as not responding. Also I do not see that any unexpected app is using resources. This has gone on for several days now but was never a problem before.
Mac Pro, macOS 10.15