exercise warning

Sarah,
I've had back problems for the past 20 years, on average i strain my back resulting in servere nerve pain, around twice a year.
reading your article on the 3 exercises performed with your backblock, it was proceeded with a warning about not performing these exercises if you had experienced servere back pain in the last twelve months.
Just curious as to why a long period before you can commence exercises from an injury. Does this mean l can't perform your routine or i should ask my gp first.
As i write i am lying on couch, pinched nerve 5 days ago have continuely over that period reinjured it with excruciating pain abut five times, each time having to rest it before i can move, let alone stand up.
Saw gp yesterday just told me to keep moving and gave me sime pain killers.
Should i keep moving if i do, no matter how careful i am, unlike other times it seems to flare up without warning. Will this result in more damage, is it part of the healing process or could it be something that the gp missed.
thanks tony