Symptoms affecting quality of voice tend to worsen after speaking for long periods of time, or when speaking with increased volume. Many individuals who use their voice professionally find even a slight presence of symptoms to be problematic. However, some voice professionals are not impacted by the presence of vocal cysts. Vocal Dynamics
Vocal fold cysts cause the properties of the vocal folds to change. When a cyst is present on a vocal fold, the cover of the vocal fold becomes more stiff and increases in mass. The increased mass and stiffness tends to result in hyperkinetic muscular movement during phonation. Hyperkinetic movement is characterized by increased rigidity in the affected vocal fold(s). This hyperkinetic movement results in the voice being perceived as hoarse. (see Signs and Symptoms) Specifically, the presence of a vocal fold cyst leads to an asynchronous mucosal wave of the vocal folds during phonation. Causes
There are several possible causes of vocal fold cysts: 

They can be congenital. They can result from the blockage of a mucous glands excretory duct. In this case, they are sometimes referred to as retention cysts. They can be the result of phonotrauma. Phonotrauma refers to behaviours that can lead to vocal fold injuries, such as vocal overuse (i.e. too much speaking), vocal misuse (i.e. speaking in an unnaturally high or low pitch), or vocal abuse (i.e. yelling or whispering for prolonged periods). Vocal folds vibrate during phonation resulting in repeated collisions of the right and left vocal folds.
Typically, patients can resume speaking activities in 7–30 days following surgery, and singing activities 30–90 days post-surgery.Up to 20% of patients show scarring, polyps or vascular changes of the vocal folds following surgery. In severe cases, these resulting symptoms may require further surgery. The patient must always be aware of the impact and potential complications of surgery on their voice, especially if the voice is heavily used occupationally. In these cases, post-operative therapy should be discussed. See also
Vocal fold nodule

References
External links
Vocal Cord / Voice Disorder Community - Online Support
VoiceInfo.org
Photo Library at VoiceInfo.org