Hi, !
I am sorry you are experiencing these issues. First off, we always suggest talking to your physician any time you experience new or worsening symptoms, for your safety. It sounds like you have discussed the migraines with your neurologist, and that's good! Does he/she have any suggestions for managing, treating, or preventing the migraines?
That said, there does seem to be a link between MS and migraines. You can read a bit more about it here -- https://multiplesclerosis.net/living-with-ms/migraines. Also, check out the many member comments following the piece.
And, while it's good to get your knee checked out to make sure something else isn't going on, but knees giving out at random can also be related to MS. It can be a frustrating issue and one that's hard to plan for, but it sounds like you are planning ahead and wearing a brace. Does the brace work pretty well?
Best, Erin, MultipleSclerosis.net Team Member.