Oh dear.. your hand hurts too? It is tough when it hurts everywhere. Sorry you have to live through the pain. Ya try to strap it around the arm or leg and see. Mine didn't really work, the app kinda get stuck sometimes until I shake the phone really hard haha.
Ah, I bought the Fitbit from one of the electonic/computer shops near by place but you should be able to find it there too:
https://www.fitbit.com/eu/store

Mine is the Fitbit Inspire HR - about 100 euros? But you got a watch tracker too right? Just that it doesn't sync with Actifit.