Snuffy, A lot of the OEM shower wands have a restrictor in the line. Just unscrew the wand from the hose and you will see what looks like a washer with a small hole in it. Remove it and screw the wand back on and it should wake up that wimpy shower head. Don't throw the washer/restrictor away in case you spend some time
boondocking where you need to be stingy with water.