I Had A Spinal Fusion At L4-L5 And L5-S1 About

I had a spinal fusion at L4-L5 and L5-S1 about 6 months ago. After I had the surgery I have had relief from pain since all but I am having migraines last up to 3 weeks. Now with my migraines I am having tingling in my feet and some muscle spams everywhere. With pain in my low back where I had the surgery. Are my migraines from the surgery or what do you think is going on.