Here's from that Stanford / Konstan article. Possibly all or possibly only part of it is accurate, and no doubt digging in to the details will be helpul, especially if we could prepare a "concordance" of every time one of these words appears.
But one thing I can say for sure - a strictly academic approach can easily make a normal person's eyes glaze over and lead too all sorts of doubt and uncertainty if not handled carefully. Almost like the letter to Menoeceus as to religion being preferable to hard determinism, I could see some people saying "save me God from these incessant vocabulary drills!"
QuoteThe ability to reason or calculate (logismos) cannot be a function of images. It is the faculty that lets us infer by analogy from the visible world to the invisible, and also that with which we may recognize that not all pleasures are to be chosen at all times, since some immediate pleasures may lead to long-term pain or harm (Letter to Menoeceus = LM 129). What is more, one must know something about the nature of pleasure in order to pursue it rationally, and likewise for pain. Epicurus, it appears, uses the terms pleasure and pain (hêdonê, algêdôn) strictly in reference to physical pathê or sensations, that is, those that are experienced via the non-rational soul that is distributed throughout the body. As for the rational part or mind, we have positive and negative experiences through it too. Most prominent among the negative mental states is fear, above all the fear of unreal dangers, such as death. Death, Epicurus insists, is nothing to us, since while we exist, our death is not, and when our death occurs, we do not exist (LM 124–25); but if one is frightened by the empty name of death, the fear will persist since we must all eventually die. This fear is one source of perturbation (tarakhê), and is a worse curse than physical pain itself; the absence of such fear is ataraxy, lack of perturbation, and ataraxy, together with freedom from physical pain, is one way of specifying the goal of life, for Epicurus.
There are also positive states of mind, which Epicurus identifies by the special term khara (joy), as opposed to hêdonê (pleasure, i.e., physical pleasure). These states too depend on belief, whether true or false. But Epicurus does not treat khara as an end, or part of the end for living: rather, he tends to describe the goal by negation, as freedom from bodily pain and mental disturbance (LM 128). However, happiness (eudaimonia), according to Epicurus, is not simply a neutral or privative condition but rather a form of pleasure in its own right — what Epicurus called catastematic or (following Cicero’s Latin translation) “static” as opposed to “kinetic” pleasure. Although the precise nature of this distinction is debated, kinetic pleasures seem to be of the non-necessary kind (see below), such as those resulting from agreeable odors or sounds, rather than deriving from replenishment, as in the case of hunger or thirst. The philosophical school known as the Cyrenaics advocated increasing desires and seeking ever new ways of gratifying them.
Epicurus objected that such pleasures are necessarily accompanied by distress, for they depend upon a lack that is painful (Plato had demonstrated the problematic nature of this kind of pleasure; see Gorgias 496C–497A, Philebus 31E–32D, 46A–50C). In addition, augmenting desires tends to intensify rather than reduce the mental agitation (a distressful state of mind) that Epicurean philosophy sought to eliminate. Catastematic pleasure, on the contrary, is (or is taken in) a state rather than a process: it is the pleasure that accompanies well-being as such. The Cyrenaics and others, such as Cicero, maintained, in turn, that this condition is not pleasurable but rather neutral — neither pleasurable nor painful.