can't remove old shower head

i know i dont have much hand strength, but i know i have changed shower heads before but cant get this current one off. cant seem to get a grip with the wrench. what am i doing wrong is there another tool you can suggest? thanks!

If it's just the showerhead it shouldn't be that hard. Most of the heads I've put on barely require the use of a wrench for tightening. But if you're putting that much torque on it you should be careful and hold the shower arm with another wrench was your trying to turn the head.
Be careful not to scratch the chrome. Maybe some pros here have a secret way of doing that w/out scratching it.