I'm 30 years old and have spent 10 - 14 hours a day seated for several years now, and recently have started suffering from lower back pain and stiffness. I decided to start stretching, and what I do is essentially the plow pose. It seems to be mostly beneficial, but some of the immediate effects make me a bit concerned.
Sometimes entering the pose takes time because I can't quite get my feet to touch the ground from the get-go. I feel an intense sensation of heat in my entire lower body and my hands, and when I do get my feet to touch the ground, there are very uncomfortable muscle spasms (uncomfortable enough to make me clench my teeth) in my hands and legs that last maybe 5 - 10 seconds before my body finally calms down and I can stay comfortably in the position, I usually hold it for up to 1 minute. When I get up, there is moderate numbness in my legs; I can stand, but I would not be able to run and walking is difficult. This will also pass quickly. Doing the pose alleviates stiffness and pain in my lower back for the rest of the day.
I have never experienced anything like above before when stretching. Should I be worried?