Who is your doctor? What are your other symptoms? What is your doctor saying?
Migraines and tinnitus would not be my only reason for having surgery. I have Eagles bilaterally. I have tinnitus on one side. The only symptom at all. Otherwise, no pain. The tinnitus is annoying. I have suggestions, a pill that you can buy in the drugstore with mostly b vitamins and bioflavinoids specifically for tinnitus Lipoflavinoids. A maroon box, Take 3 a day, it helps. May not get rid of it, but might help a lot. It did a lot for me. You must take for at least a month to get any results.
My ENT recommended it it is Over the Counter and it might not help everyone, but it did help me. I don't take it anymore because I can't tolerate ascorbic acid that is their form of Vitamin C. I would if not for that.
If I start having pain on the side with the tinnitus, I would have surgery and really hope to lose the tinnitus. I have had it for 10 years. Sometimes it is maddening, but not all the time.
There are non surgical treatments for migraines. Migraines and tinnitus, have your blood pressure checked lately?