One thing I have learned from being on this site, is that anxiety can cause ANY and ALL types of symptoms. One problem is that we focus so much on our bodies that every small pain or symptom becomes exaggerated by this focus.
If you can, try to find something that will distract you......start focusing outside instead of inside. One thing that helps me a lot is to volunteer somewhere. We have a local soup kitchen, and when I see the folks who are there, it makes me see how good I really have it. Another good place to volunteer is a nursing home.....perhaps read to someone there.
I know you have had many tests, but you didn't mention whether or not you are being treated for your anxiety. There are many meds that can help, and therapy also helps.
Good luck to you.