t2p

Actually - shoes that are too flexible / without proper support can lead to plantar fasciitis and aggravate it - especially in cases of a 'high arch'.

They allow the tendons (plantar fascia) to flex excessively - which can lead to plantar fasciitis and / or heel / 'bone spurs'.

This is one reason orthotics are often prescribed for plantar fascia problems - they provide additional / proper support for the arch / tendons and will reduce the amount of flex in this area (often from pronation).

A more stiff / neutral or stable support type shoe is then often recommended (or prescribed).

Distance runners that pronate will often run into plantar fascia problems - and then seek out a more stable / less flexible shoe - or in more severe cases will use orthotics.

'Shin splints' (and similar) can also be involved / related to plantar fascia problems - often from muscle imbalance (calf vs shin) / excessive increases in intensity / duration etc. This is one reason calf / achilles stretching is recommended and prescribed.

( severe cases of 'shin splints' can lead to 'compartment syndrome' / ischemia - you don't want to go there)

I could go on ... initially ran into these issues as a cyclist and runner years ago - and then more recently as a baseball coach from years / repetitive landing on forefoot when pitching batting practice and outfield reps (hitting fungo / fly balls to outfield).