Hyperacusis (senstivity to noise) is VERY real.
However, when you have it you develop a phobia of sound. If you KNOW a sound will be loud, you can probably handle it.
When you hear a loud unexpected sound, you get "anxious" and react to it, partly because you don't know HOW your going to react.
Basically -- you start to avoid noise because you are afraid of it, because it hurts you. SOmetimes though, the hurt is very minimal.
it's confusing.. and I have it.. and it sucks!
The search for a diagnosis is long and painful...