What Is It Like To Have Extremely Sensitive Hearing?
Hyperacusis.

http://perso.orange.fr/martyprod/Misc_Hyperacusis_en.html

Manageing Chronic Tinnitus As A Phantom Auditory Pain
Robert L. Folmer , Ph.D., Assistant Professor Of Otolaryngology, Oregon Health Sciences University, Portland , OR

http://www.healthyhearing.com/library/article_content.asp?article_id=64