Not new to exercise, I've done it on and off for years and used to lift fairly heavy (DL 130kg) before I randomly herniated a disc and had spinal surgery
I can't feel my glutes 
So I do a barre class where everyone is "owww my bum" and I'm
my outer hip will burn and my hamstring cramps
Just done a 20 min glutes and lower body workout and nothing in my glutes at all
How can I help them?! I work sitting down all day and after my op I know they're weak but I can't even activate them as such. I wanted to protect my lower back which means stronger glutes...