How do you unscrew shower head that is secured too tight or has threads that are siezed in place?

Answer 1

try the application of a moderate amount of heat

Most heads are on a ball swivel, so you need to hold the collar of the head and not the head. You use either a pipe wrench or channel lock pliers and hold the collar with a wrench

and remove it. In 20 years, I have never had to apply heat to remove one.