Everyone!
I hope you are all well or on your way there!
Hello, GrowThroughIt. On my way there, that'd be my answer.

I don't want to spend too much time dwelling on particular instances (as for various reason it might not make for very pleasant reading)! Suffice to say, my parents are both controlling, needy, my mother is narcissistic, bullies, rude, arrogant, condescending & childish amongst other things.
Your father's saying that you are not a good son and "not as great as you think you are" sounds narcissistic to me, too. Margalis Fjelstad writes in
Stop Caretaking the Borderline or Narcissist that NP/BP personalities feel intense emotions, don't know where they come from, and blame other people for them. There is also the theory of the "moral defense/complementary moral defense", that is, the narcissist claims to be the source of all the good, and the other person is the source of all the bad (see
www.danielshawlcsw.com/wp-content/uploads/2015/10/Enter_Ghosts.pdf)
I can see how their treatment has led me to hold a lot of shame and guilt. Guilt for being born (which would always be placed on me), and guilt for messing up their life (especially my Dad's, who said on numerous occasions that his life was better before I was born and because of me it's now *expletive deleted*
Well, I'm sure you can understand intellectually that you didn't ask to be born. However, one of my analogies for it is that there's a shame "hot potato" and when a parent tosses it to a child, the child does not have the understanding or developmental capacity to toss it away.
Perhaps you can begin to remind yourself that the shame belongs to your parents, not you, even if you don't feel and live by that yet. Notice that doing this may lead to feelings of anger or a surge of energy. Notice that that can be difficult to stay present with (sure is for me), because claiming this rightful self (yep, totally rightful) would have been dangerous in your FOO.
You may find some grief in there too, I have. Also a kind of repulsion or disgust at some of the lies I was forced to accept as true. I'm realizing I was "recruited" to hide family secrets more than i was previously aware of.
I feel at times, deep shame & guilt for example, for not standing up for myself at certain times (whereas other times I did) to people who bullied and belittled me, as I was growing up. I feel like there were times where people stepped all over me, and I let them. I hold extreme anger and resentment to these people, to the point where I feel like lashing out (violence in my home and outside the home were second nature to those of us who grew up in this environment).
I understand. However, would it be a helpful perspective if I said that given all the facts and sequences of events of your upbringing, it would have been impossible for you to choose differently? As you gain awareness now and heal, and take steps like posting here and getting therapy, new options may open to you as well as the skills for exercising them, but in the past it could not have been different?
Could it be a case of Person A belittles/bullies me > I feel anger > Keep it bottled up as I couldn't let it all out as a child > The shame I feel is intensified due to the core shame & guilt that I feel? Is that why I can't get over these instances?
That makes sense to me! When I take risks in relating to people (being more spontaneous and expressive, for example) I can have backlashes of anxiety... .which I believe is that old superego/inner domineering parent stepping in and saying "Not a chance!" Perhaps anger feels so forbidden for you that as self-protection it gets squashed with shame and guilt before any of it even gets out.
The good news, I suppose, is that that suggests a high intensity of emotional energy currently locked up in you, which, once you are able to be present with it, feel it and express it, will serve as "fuel" for your life.
Will getting over the core trauma help me on my way to letting go and then live a life I deserve to?
Am I even correct in thinking that I suffer from deep core trauma shame and guilt?
I am beginning to think that healing is less about "getting over the core trauma" (although some understanding may be necessary) and more about reclaiming the right to feel all of one's feelings. Some people find they require an attuned person e.g. a therapist in order to accomplish this. Given what you said about anger, I think it might be helpful to find someone comfortable with the emotion of anger, in whose company you can feel it towards the right people for the right reasons.
eeks