Left Foot Arch Pain

I have flat feet and a history of plantar fasciitis so maybe it’s flaring up but it’s doing so in a weird way.

In 3 of my last 4 runs my left foot has taken about 2miles to “warm up”. For 20ish minutes the arch in my left foot feels tight and painful - a dull pain. I usually stop to stretch a bit and walk for 10-15secs and after repeating that for the 20ish minutes it starts to feel like it loosen up and pretty normal.

What could be going on here? Any extra feet activation before my runs maybe?

For context: I do warm up before every run and wear Clifton 8/9s. Actually started on my last run with my 8s last week and realized they were pretty worn out so got the 9s to stay in the Clifton family and this has now happened twice with the 9s