Process of removing mold from behind shower tile
Start out by using a pry bar and snapping the tiles off the drywall. This way you'll avoid cracking and breaking them up. Then remove the drywall by just pulling it off the studs. Then you'll have to go back and pull out all the screws and nails. Hopefully the framing studs will not have to be removed and you can just treat them with some vinegar to kill the mold and mildew. Notice that I said vinegar and not bleach. Bleach kills surface mold but does not sink in to kill the roots whereas vinegar does. If the studs are rotten, best to remove them plate to plate and replace the whole stud. Remember to wear good work gloves because the tile and debris will cut you to shreds. Wear eye protection too along with a dust mask.