Sudden exertions causing acute pain at ankle/top of foot

A few months ago I experienced an acute pain while playing tennis. I was turning/launching off my right foot, and the pain was at the top of the foot - where it meets the ankle (see attached image). The pain was coming from the muscle(s) running from the bottom of the shin to the top of the foot. It subsided after a few minutes, but happened again whenever I launched or turned on that foot.

Ever since then I have been experiencing similar extreme bursts of pain at the same location whenever I make certain types of sudden movement with my foot. The most extreme pain is caused when I simply remove my sock quickly. This involves a sudden upwards movement of the foot, as well as a slight rotation. When this happens I am in extreme pain throbbing pain for a minute or two before it dies down.

The pain also occurs when I launch/turn on that foot while playing tennis or badminton. It can also happen when I am walking upstairs (on deep steps), or randomly when walking down the street. I have been wearing an ankle brace when playing badminton for the last 5 years, following an ankle sprain, but have had to stop wearing it because it makes the pain worse - probably because it causes the sports shoe to fit more tightly around the foot. I'm not sure if this might have contributed to the cause of the problem.

There is no restricted movement in any direction compared to my other foot. I can stand, crouch, stretch, lift, and stand on one leg without any pain. I only experience the pain when I make sudden exertions.

I saw a physio about it today. He said he thought it might be a problem with the subtalar joint (becoming inflamed), and has simply recommended some exercises to strengthen the muscles in that area - nothing to explicitly explain/address the acute pain. He tried a number of exercises on me. The only one that reproduced the pain was a calf lift/stretch - against a wall. This didn't involve any rotation of the joint - just a simple up and down motion.

I was wondering whether anyone else had experienced similar, and can suggest other possible causes/treatments?