Hi, I feel for you! Astrocycoma age 6 lower back came back two more times before age 12.

I'm 43 now Glioblastoma t6-t8 sigh... I'll be ok
The pain you have sounds crazy but force yourself to move. I was running a lot before this last episode. Even weights, ok so my theory is when you breath out it releases so much pain. I'm not qualified to really have a theory but, maybe? I cannot feel my right leg, haven't since a child so I fall a lot especially around the corners of a track lol... My kid loved when that happened.. You are so young, I hope you can overcome the pain.