Hello @pinkskyinthemorning and welcome to Mayo Clinic Connect. You are asking a good question about this new issue and whether it may be related to medication. I went to Mayo Clinic's website. Here is a link with information about Diltiazem: https://www.mayoclinic.org/drugs-supplements/diltiazem-oral-route/description/drg-20071775

If you scroll down the webpage, you will see a list of side effects, including sore throat, changes in voice, swallowing problems, and hoarseness. Partial paralysis of the vocal cord is not listed. Have you been referred to an otolaryngologist for the examination and treatment of your vocal cords?