I'm on Prevacid for my GERD and have been for about 7 years and yes you are right, it did start with my meds.

My voice faded also. Bill use to say my voice didn't carry. He would say I wasn't talking loud enough until I got mad at him and then he'd say it was too loud. I told him to make up his mind. LOL It's better now though. I spent a long time in Physical Therapy for my TOS, RSD, and Fibro and they stretched my upperchest area to help loosen up things up there.

Mine wasn't from the RSD though, mine was from the TOS. At least I am thinking that.

Hope you start feeling better.

Ada