The most annoying thing about MI is that if you have a health problem, they think it's in your head. It takes persistence to get people to see you as someone other than a collection of acronyms from the DSM. Read this https://en.m.wikipedia.org/wiki/Nerve_conduction_study
And see if you can have the test.
But don't stop fighting for pain relief. It's YOUR body and you have the right to be free from pain and not just dismissed as a fuss body.