I had a spinal laminectomy 3 months ago and still have some of the same pain symptoms as before the surgery. The pain comes and goes. Exercises?

It depends. You should follow the instruction of your surgeon about exercise. It is impossible to give you advise without reviewing your entire case. In general with any spine problem exercise and keeping in shape is desirable.
What levels? You should have been offered physical therapy. They can offer you exercises you can do at home.