Need help with Voice to text software for Mac users

Hello everyone,

    My name is Dan from Buffalo NY.  I am disabled due to a rare spinal condition that has aged my spine 3x my age.  I am 45 and it has been estimated that my spine is about 130.  Needless to say, I am in a lot of pain and can only sit up for short periods of time.

     What I am looking for (with my Mac) is voice to text software that I can use to write stories with.  I plan to write short stories, novels and screenplays.  I need advice on what to use.  I am not computer savvy (I didn't know my mac had text edit until someone showed me).  So, I am not real sound with how to do stuff and need pretty basic answers.  Is there any free software that can be used?  Since I am disabled, I can't work anymore and only get SSD right now (until 65, then my pensions kick in, but that's a long time away).  

     I refuse to just give up on my dream.  Just because my body is breaking down doesn't mean my mind has to.  So, this is very important to me.  Any software you tell me to use would have to be able to handle standard creative writing needs.  Dialog, paragraphs etc.  I know screenwriting might just be a template speciality, so, I will have to see if the writing program you have me look into can handle templates, but, one problem at a time.  I have a lot of great ideas and with technology so great now, I am hoping that what is in my head might be able to be read or seen (in the case of movies) by others.  

thank u all in advance for any help.  I know everyone is busy.  It is really appreciated.

Dan