13 Symptoms of Multiple Sclerosis July 25, 2016 by admin In Social Clips. 0 (0) 3. Muscle spasms Muscle spasms, causing stiffness in muscles of the limbs and most involuntary muscles. More than 500,000 Americans suffer from spasticity; when it occurs in the upper arm, it can cause muscle stiffness, spasms, flexing, and twitching. Print This Page How useful was this post? Click on a star to rate it! Submit Rating Average rating 0 / 5. Vote count: 0 No votes so far! Be the first to rate this post. As you found this post useful... Follow us on social media! We are sorry that this post was not useful for you! Let us improve this post! Tell us how we can improve this post? Submit Feedback Pages: 1 2 3 4 5 6 7 8 9 10 11 12 13