I've majored in computer science (BSc: close to MIS, MSc: advanced software engineering), I've worked on dissertations on totally different topics in every stage at college, now I'm planning to do a PhD and I've been looking at different topics from various sub-fields but I frankly can't pin one to use as a starting point. I would say that I like X topic or Y and when I look closer at the papers being published in the field they seem too obscure to me and I can barely comprehend their abstracts. For example, I was searching for starting point in solving concurrency problems in software or even advance such technique since I felt it's what I want to do and what I know that would keep me motivated but I frankly couldn't find anything, I've looked at publications that reference famous papers/book (things I've researched very briefly) like communicating sequential processes and cooperating sequential processes but there was nothing that could give me a good start.
My questions here, am I looking in the wrong sub-field? I know I'm highly motivated by the previously mentioned area but do I understand enough to enter such area? I've seen people jump from psychology to computer science at PhD level and I wonder how someone could do such thing. Also am I even a PhD material if I can't pass this stage?
Note: the topics of my past dissertations were on AI and online social communities