This thread has been really helpful. I'd been wondering what causes sound sensitivity.

The largest issue for me has been dealing with sounds over the cellphone. If my friend is cleaning or clanking things in the background while we're talking on the phone, I start jumping out of my skin and have to hold the phone away. We have an agreement now to hang up if he's going to run a blender or wash dishes etc.
Also, when he gets caught up in a story and starts talking in a higher pitch on the phone, I lose ability to understand what the heck he's saying.

Simultaneously, I've noticed a significant loss of hearing in my left ear. Prior to the diagnosis or having researched anything about MG, I was wondering aloud how I could be more sensitive to sound while simultaneously experiencing hearing loss.