I have been doing yoga for a while now and it seems that I can't make any progress with one-legged balance poses (tree pose, half moon pose, warrior III, standing pigeon and so on) and, to a lesser extent, with high lunges. I am pretty sure the problem comes from my flat feet. I can't find ease in these poses and I feel a lot of pressure around the Achille's tendon.
Does anyone face the same issues? Do you have any advices to find ease in these poses when having flat feet?
Thanks in advance