The term “Extraforaminal stenosis” does not allow me to understand your diagnosis. Stenosis can be lateral recess stenosis, foraminal stenosis or central stenosis. If you have a disc herniation or even a large bone spur lateral to the foramen, that would be called a far lateral herniation or spur and I assume that is what you mean. If this is what the diagnosis is, then your symptoms may make sense. Sitting stretches the nerve over the herniation or spur and would cause onset of symptoms. Symptoms would also be aggravated by bending over to tie your shoe or pick something up off the ground.
You state steroids did not help. Were these in the form of an injection or pill? A diagnostic injection most likely would lead to the correct diagnosis. See the section on an SNRB (selective nerve root block) and keeping a pain diary on the web site.