An addendum I'd add to my post #5 above is:
Positive feelings (ie, pleasure) can be categorized as "positive" because they are conducive, favorable, helpful, or beneficial to life or living.
Negative feelings (ie, pain) can be categorized as "negative" because they are unfavorable, unhelpful, detrimental, contrary to, or damaging to life or living.
Negative feelings are inevitable for living, mortal beings and those feelings are valuable by signaling what to avoid or flee from. But we need not embrace or glorify them. And yes, some negative feeling/pain is sometimes necessary for achieving positive feelings/pleasure by one's future self. My go to example is exercise. Those who claim to glorify pain as in "no pain, no gain" are actually saying that they will willingly experience pain but you know what... They leave out the gain, which is taking pleasure in the results of their action!