Jeff is right...the folks at Vanderbilt are pioneers in the study of "voice". I would also highly recommend the people at the Pittsburgh Center for Voice (many studied at Vandy...Dr. Jackie Gartner-Schmidt is terrific and Dr. Clark Rosen is revered as a laryngologist!)) As a professional who has had numerous voice-issues over the past 7 years, I can attest to the horrors of not being able to do effectively what was once seemingly effortless. After years of therapy, exams, going to the next doctor and the next....I finally had the fundoplication surgery 4 years ago. If you're experiencing the effects of acid reflux (burning, excessive throat-clearing, lack of power and range) and OTC products or prescriptions are not helping, ask a good laryngologist or gastroenterologist about the nissin fundo surgery. It's the gold-standard.
However, it's not a cure-all for everyone, including me. Do some research on LPR, too. Often called "the silent reflux", LPR (or non-acid reflux) many times doesn't have the typical symptoms of acid reflux. The problem is that acid, bile, and other substances make their way up through the esophagus and "pool" in the voice-box. The esophagus has much greater healing properties than does the larynx and the vocal folds! Chronic throat-clearing can be a sure sign of LPR effects. Be careful of diet, eating late at night, and certainly DON'T SMOKE!!
If an ENT cannot diagnose, search out a good laryngologist who can scope your vocal cords and start a treatment plan. Reflux sucks!! (hey, that rhymed!) Together with some decent exercises, diet modification, medication, and maybe even voice-therapy, you'll find some relief. For me, there's been no magic cure-all. (unfortunately) Good luck!