yes. Mine does. If I am up on my legs long, they hurt so bad I could scream. Especially if I get in the mood to clean up. By that afternoon, I can hardly walk on them. Doc says not related to MG but it is a funny thing, when I was diagnosed and began my medicine, it totally went away. Now, it has come back and my fault. Playing around with my medicine and played havoc. But yes, the legs hurt and feel heavy.