Baseball518,
The expected outcome after decompression for cervical stenosis is relief of the radicular symptoms. If there is neck pain, that is more variable in terms of pain relief.
After the surgery, there will be some post-op pain, but this can be treated with pain medicine. As to activity levels, you will need to discuss this with your surgeon. Every surgeon has his/her own protocol for post-op activity and rehab.
Good luck.