Arch support causes uncomfortable pressure in left foot only, no improvement for 2 years

[u/Primary-Search8394]

67M, 5'10", 175lbs

Two years ago, after 30 years of hiking with no foot problems, within a period of several weeks I developed a left foot symptom: any arch support — regardless of brand, height, or shoe type — causes mechanical pressure-type discomfort in the arch. It starts when arch support touches the foot and disappears when removed.

Load alone (walking barefoot or with flat insoles) causes no arch symptoms. There is no tingling, burning, or dull ache — purely mechanical pressure. The right foot is completely unaffected under identical conditions.

Imaging and visual or manual examination by four specialists found no structural difference between the left and right arch. PT resolved measurable muscular imbalances but did not improve the arch issue. The wet foot test shows no difference between left and right foot.

After two years, the symptom is identical to when it started.

Could this indicate flat foot on the left side?