Talar compression syndrome means there is some impingement happening in the posterior portion of the ankle joint. Other medical personnel might call your problem os trigonum syndrome or posterior ankle impingement syndrome or posterior tibiotalar compression syndrome. No matter what they name it—it means you are having trouble moving your ankle through pointing and flexing.
I recommend you go to a physician who understands the physical demands of dance to assess your situation. The evaluation, which ideally would combine listening to your history, manipulating the joint to test its mobility and getting a look inside with appropriate imaging techniques, should give you a clearer idea of what’s going on.
You may have an issue with an os trigonum, a tiny chip of bone related to the talus that can get caught in the joint and create swelling that causes irritation when pointing. The posterior tibialis tendon may be impaired, especially if there has been a history of pronating.
If the weight is not centered through the ankle and feet, the arches may not be distributing the weight correctly, and an orthotic may temporarily help. (In many cases, this is the cause of the syndrome, because the weight of the body is not going through the foot correctly, and it alters the arch formation to create impingement.) An accurate assessment of your alignment is key for successful recovery. When an injury drags on for months, it can set up compensatory patterns that will also need to be addressed during your recovery period.
Watch your standing and walking posture to stay in good alignment and follow the guidance of your PT for what exercises to do.