E'phobia is part of part of trauma and is very common. You could be right - all the things you mention could have contributed to your issue. Also true is that there's growing interest in and acceptance of the ongoing effects of physical and emotional pain pre-conscious memory. Google for the work of Dr K J S Anand and the NY Times articles that came from his work. Your 1970 surgery was well before attitudes on early trauma started to change.
My phobias arose from my parents' stories and what they stonewalled about, plus my deep embarrassment about a prominent scar which raised questions I couldn't at the time answer. This was trauma inducing. But I'm also sure all this connected with somatic (body) memories older and deeper in my psyche. This is what we're finding now.
Like you, my stuff has had all sorts of consequences, but somehow my Christian faith wasn't affected.