I have multiple sclerosis. the last few days my i have lower back pain and my legs keep bucking and im struggling to walk, is this ms related ? who should i turn to.

Impossible to tell: It is impossible to tell without an examination and appropriate studies. Start with your neurologist.

It is imperative to rule out an exacerbation of your MS immediately, as you need treatment if indeed a relapse has occurred. If this is correct, the low back pain would be secondary, and less likely the primary cause. Presume you have a neurologist who should be contacted. Hopefully, you are taking a high efficacy medication, and if not, this would need modification.