What is wrong with my chest?

Hello everyone, I am new to this forum as I am searching for some possible answers as to what is wrong with my right pectoral. In august of 2016 I was involved a head on car crash that I was lucky to survive in, I came away basically unscathed aside from pain and a few small cuts but there was nothing serious. I got an x-ray done and there was no broken bones anywhere and the people at the hospital said I checked out fine. About a week or so after I was looking in the mirror and i saw that one of my pectorals seemed rounder and less defined than the other, at first I thought it was nothing but when I flexed I saw that I could not flex the entire part of my right pec and it looked much smaller than the other, and after a few workout sessions I realized my right pectoral was always a lot more sore than my left, and this was odd because I had done these workouts before and I had never had this issue arise. From then until now I figured it was just a pectoral strain that would heal over time and go back to looking like the way it did before I was in an accident, but it didn't. I don't really have much soreness/pain in it anymore and it doesn't really affect me outside of the fact that it looks abnormal, but I would like to know what the issue is and if I will ever get full definition and symmetry back in my chest. I went to my doctor yesterday and had him check it out and he doesn't think there is any muscular damage done, no tears or strains, he thinks that there is a possible nerve impingement and recommended I see a chiropractor and see if he can find something wrong with my spinal chord/ribcage that is pressing on the nerves and not allowing me to flex my entire pectoral. I have attached a few pictures that help you get a better idea of what I'm working with.

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One picture is resting, one picture is flexing, and the one where i have my arms and shoulders raised I am trying to show the small indent where I can not seem to get the muscle to flex. Any helpful response is appreciated!