Welcome. I get tightness in my legs. The best thing I have found is plenty of stretching. My Neuro told me to keep stretching the rest of my life in order to maintain use of my muscles and to help prevent loss. You might also want to make sure you are consuming enough calcium and maintaining sufficient hydration. Dehydration can cause cramping and knotting of the muscles.
When the tightness occurs around your mid-section or chest, that is often called a "MS Hug". While I get the occasional "hug", my legs are bothered the most.
I hope you can find a resolution!!