Yes, I've had this. How on earth did you get an ultrasound??? I've had it over 2yrs and no xrays/scans or anything! Saw podiatrist, osteo, changed shoes & gait assessment all at my own expense. I did get some NHS physio, but this amounted to 4 session online over 6mths!!! Despite the fact I'd already paid for weekly physio myself for several months! Nothing helped.
I lost 10kg, and during covid put it all back on, yet saw no difference in pain at all when i was lighter. I did all the stretches and exercises recommended, only wore specific trainers all the time, night splint, insoles etc etc.
I was awaiting a specialist, phone appointment and woke up pain free one day!!! The only difference is that I stopped doing the physio exercises daily a few weeks beforehand. No idea if its related, but I cannot think of anything else that changed. 
I'm still awaiting the consultant appointment, but was advised that shock therapy or a steroid injection might be the next steps.
Have you seen a specialist or awaiting an appointment with one?