I think I agree w/Q of Quimica.
There are not THAT many things you can do as a physician that are THAT different than what you are doing as a PA. Yes, you would have slightly more clinical autonomy, but not even that much. And is it really worth the extra time and expense. You are going to be giving up 7 years of PA salary, at minimum, plus whatever extra money you have to spend on the whole admissions process (and your time, which is worth money). You will get no salary for 4 years plus have med school expenses, and then 3 years of residency salary which is probably 1/2 of what you are getting as a PA.
Unless you want to go do academic medicine or do a lot of surgical procedures, I can't really see going this direction. If you become a really skilled PA, I would think you will write your ticket, in terms of job offers, and then people tend to give you more autonomy as you get better at things. Of course there are some limitations to your degree, and what you will be allowed to do with it, but we (MD's) run up against that all the time as well, and I think you would find being in training another 7+ years pretty painful.
You better make sure you have a good reason before you decide to go through all this - I'm not saying you don't or it is impossible to have a good reason to do this in your situation, but I think it would be a wrong choice for many in your shoes.