Hi, sickmm. Welcome to the forum!

Imaging of the brain and chest are not necessarily going to be revealing. They can rule out other conditions, but negative tests can't rule any in.

On the off chance that you have MG, you should not be running, especially not in the heat. Heat can make MG exponentially worse.

Have you brought up the possibility of MG to a neuro. Tread carefully, many neuros don't like when patients think they may have a disease! You can always go see a good neuro-ophthalmologist and have them assess your eyelids/vision. They are not the same as a regular ophthalmologist. They can check to see if you have fatigable eyelid muscles or have double vision.

The breathing tests you should have are MIP and MEP. Those are specific to neurological diseases. They tend to go downhill the more you do if MG is not treated. Find a good pulmonologist who can run those tests.

If you have one eyelid that is droopy, pull up on it. Does that one go up, while the other one goes down? That's called "enhanced ptosis." Pretty typical of MG. Does that ptosis worsen if you gaze upward for 20 to 30 seconds? Take photos before that and afterward. Then do the ice pack test again and take more photos. Using a cold washcloth works too. Use the same angle, head tilt, lighting, etc. for those pics.

You can always ask for the AChR antibody tests. Even an internist can run those. Try to have them sent to Mayo, since they tend to be more accurate.

Just take it easy. People who do have MG can go into what is called a MG crisis, where they can't move, breathe, or swallow well. If that happens, you need to dial 911. Doesn't matter if you have a diagnosis. If you have MG, the best place for you is in a hospital. Don't drive either! A MG crisis can happen quite quickly and there's no way to know how worse symptoms will become or how rapidly.

I'm not saying that to scare you, but to make you prepared just in case.

I hope you can figure out what is going on. Please let us know how else we might help, okay?

Annie