Hi, i have ms and recently my right knee gives out and i lose my balance, is this something i need to be worry about it and what i need to do? thanks?

Please contact your neurologist for a reevaluation.

Please see your doctor for an evaluation. Knee giving out puts you at risk of falling and getting injured. Wish you good health!

If you have been diagnosed with Multiple Sclerosis, presume you are followed by a neurologist, who you need to see ASAP. From your post, it is not feasible to determine if your right leg weakness is due to a relapse or secondary progression, but this needs to be appropriately handled.