as stated put the car on jack stands,,dont work on a car on a flor jack or a bumper jack,,,
if you dont have jack stands,,go to your local auto parts store,,or walmart,,buy your self a set of 2 ton jack stands,, or a pair of ramps,,even if the car wont start,,jack it up and rest the car on the ramps,,if you are a large sized guy,,, jack stands are adjustable in height,, to get the car high enough to get under it,,,
no reason to take it to a mechanic,,you have chosen to be a guy guy,,now learn to do it your self,,unless you have tons of money to throw away,,waling in to a mechanic,not knowing what your talking about , they wil take advantage of you and rob you blind,,,tons of great guys on this site that will help you out,,
you cant trun the wheels if you use ramps,jack stands let the wheels hang,making them able to turn while in the air,,
im guessing your motor mounts are old,, and sagging,making the motor sit lower,or closer to the suspension making it hard to twist the starter out from under the car,,,,
if you can turn the wheels,you should be able to twist the starter out,,if not you wil have to do one of the 2 choices,,remove the center or drop it down,,either disconnect it at the inner tie rod ends or use a puller to remove the pitman arm from the bottom of the steering box,,then there should be plenty of room,,but turning the tires will be way easier,,