I also gained over 20 pounds since my injury over two years ago.
At first the weight gain was not so much, but then I started taking Trimipramin and that made me gain weight day by bay. After quitting it one year later my weight did not drop.
Before PCS I was a sporty person, every free minute I was doing something.
During PCS the only thing that seemed to not cause any Pain was eating

So thats what I did.
Now it is so hard for me to stay away from chocolate or other sweets.
Hope we find a way to loose all that weight again, I am not comfortable with it.