I have this off and on too. I'd had it for many years before I realized it was a "thing" and had a name, and that there might be anything I could do about it.
I think it is related to a vitamin/mineral deficiency of some kind, but I've never been able to pin down exactly what. I eat a lot of iron, zinc, and b-vitamin rich foods when it happens and it tends to go away. I take supplements of B12, folate, and the other B vitamins, and a little zinc, but the supplements alone are never enough to keep it at bay completely. ...Which makes me think it might be iron-related for me.