Can acid reflux cause a high pitched voice?

Doubtful: Reflux occasionally can cause hoarseness but generally not higher pirch.

GERD: Uncontrolled reflux could give you acid taste in your mouth associated with coughing and hoarseness specially while you are sleeping. You will cough and wake up suddenly. But can happen without the cough too. Avoid eating late night. Wait 2-3 hrs after eating before going to bed. If you have gerd avoid food that give you heartburn. Like caffeine, alcohol, sodas, chocolate, spicy/fatty food.

More often, hoarse: Acid reflux certainly can impact the voice. More often it makes it lower and hoarse, hitting the range that notes shift into the "head" register. But in addition to your pcp, you might check an ENT or speech therapist with experience in this. Here's a site on your concern: http://voiceofyourlife.Com/cm/archive/articles%20on%20vocal%20health/acid%20reflux%20&%20voice.Html best wishes!