I’m guessing you have already thought about this, and the following is 100% speculation drawing from what I have learned in PT from my own injuries.
It sounds like something is getting out of place, causing tension in other places, and then it pops back where it should be. All of these different parts from the hips up to the spine and down to the ankles depend on each other so if one part of the “super assembly” gets out of whack, something else will compensate.
The physio should be able to diagnose it, but in the meantime if you know how to use athletic tape you might see if you can hold one of those spots in place. A past diagnosis of tendinitis might be a clue.
If you have not been instructed by a physical therapist or other master degree level professional, then it would likely cause more harm than good. Also all the standard stretching for runners, just as a reminder.
Please disregard this if it doesn’t sound helpful. I am really reacting from my own feelings of wanting you to protect those joints since I am worried about your pain levels. So, I want to help, but for some reason I am just full of advice. I’m sorry for that!