Can you still work? When you have spinal stenosis?

Yes. Most people can especially if the job does not require prolonged standing and walking. Not all people with spinal stenosis have symptoms and a lot have minimal symptoms or are controlled with treatment.
Depends. It would depend on the degree of spinal stenosis and upon the type of work you do or plan to do.
Spinal stenosis. Spinal stenosis in a condition wherein tissue grows around the spinal cord, causing gradual compression and pain. It's progressive and unrelenting. Unfortunately leading to debility and pain. Surgical options are available which may help, but left alone it'll cause progressive limitations. The rate of progression is unpredictable. Work may eventually become impossible.