I am trying to swim to get the serpent idol in the serpent temple. However, after I go under the water beaneath the serpent holding rooms I am unable to resurface. Has anyone else had similar problems? Does anyone know of a way to fix this?

you can only resurface at the point were you entered the pen so make use of the map facity of your character. Some have also had problems getting through the tunnel to the area were the idol is so select the character with the beast atheletics rating as lead and look down and forward to get through.