The pain is real āĀ The suffering of purgatory is likened by the saints to burning in a blazing fire. In fact, some saints have even said that the pain of purgatory is not all that different from the suffering of hell. One of the chief sources of the pain is the fact that salvation has been obtained, and yet one cannot immediately enjoy its consolations. This delay of the enjoyment of heaven leads to a spiritual agony of sorts. St. Thomas Aquinas explains it like this:
The more one longs for a thing, the more painful does deprivation of it become. And because after this life, the desire for God, the Supreme Good, is intense in the souls of the just (because this impetus toward him is not hampered by the weight of the body, and that time of enjoyment of the Perfect Good would have come) had there been no obstacle; the soul suffers enormously from the delay.
So the souls in purgatory are suffering in a very real and painful way, a way we cannot fully comprehend. We have the ability to help them and relieve them by our prayers and actions.
https://www.catholic.sg/the-forgotten-church-five-reasons-to-pray-for-the-souls-in-purgatory/?__cf_chl_f_tk=QrMJY6v1XUfb6y53aUaoB6s7mIA7RVZ7vEzPOE32h.k-1783002088-1.0.1.1-knsEI53K4Py_Lfm1rvQVeSFZgYS5ZGJcQlaBy6BhdDY