I have too, severe pain when I over do it, esp in my neck and shoulder muscles, like my head is just to heavy to carry. But over the years, my pain became more severe and my neuro said it can not be all from the MG, so she sent me to a RA and I was diagnosed with fibromyalgia. I had 18 out of 18 trigger (pain) points that they use to diag you, and you only need 10. She also said that the trauma of the MG most likely pushed me into the other. Wouldn't hurt to check out.

Hope this helps,

Barb