iPod touch 5G full charge from 20% in an hour
I have itouch 5G space grey 64gb and it charges fast when plugged into wall socket but not in computer. Is the battery damaged?
Doubtful. USB's put out less power than a plugin charger. USB's also have a bad habit of being turned off when the computer goes to sleep (sleep on a computer is a low power state, and power to USB ports is usually cut off, so if you're charging from a port that goes to sleep, you basically lose your power and it's not charging when you think it is)
Also, if the plug in charger you use happens to be an iPad charger, those put out twice the power of an iPhone one, so your iPhone and Touch will charge very quickly using iPad chargers.