Are research papers hard to read?
Unfortunately, research conferences generally do not place a premium on writing for readability. In fact, sometimes it seems the opposite is true: papers that explain their results carefully and readably, in a way that makes them easy to understand, are downgraded in the conference reviewing process because they are "too easy" while papers that could be simplified but haven't been are thought to be deep and rated highly because of it. So, if you rephrase your question to add another word, is it not just you who finds some research papers unnecessarily hard to read, then no, it is not. If you can find a survey paper on the same subject, that may be better, both because the point of a survey is to be readable and because the process of re-developing ideas while writing a survey often leads to simplifications. 

As for strategies to read papers that you find hard, one of them that I sometimes use is the following: read the introduction to find out what problem they're trying to solve and some of the basic ideas of the solution, then stop reading and think about how you might try to use those ideas to solve the problem, and then go back and compare what you thought they might be doing to what they're actually doing. That way it may become clearer which parts of the paper are just technical but not difficult detail, and which other parts contain the key ideas needed to get through the difficult parts.