If you have the money - a cheap guitar and an amp costs around
$300 while an acoustic can be as low as $30.
Normally beginners start by buying an cheap acoustic to hone basic
techniques first. It depends on how interested you are in playing
the guitar and the type of music you like that will determine which
type of guitar to get.
About the pain of pressing acoustic guitar there is really no
difference between training your muscles in the gym. While playing
the electric guitar is less painful in a way, your wrists, forearms
and fingers will still be tired from all the playing.
The most important is to buy the type of guitar to suit your type
of music. The pain and of all that shouldn't be a factor. 