pain is in
the body: as when we suffer something hurtful to the body. But the
movement of pain is always in the soul; since "the body cannot feel
pain unless the soul feel it," as Augustine says (Super Psalm. 87:4).

Reply Obj. 2: We speak of pain of the senses, not as though it were
an act of the sensitive power; but because the senses are required
for bodily pain, in the same way as for bodily pleasure.

Reply Obj. 3: Pain at the loss of good proves the goodness of the
nature, not because pain is an act of the natural appetite, but
because nature desires something as good, the removal of which being
perceived, there results the passion of pain in the sensitive
appetite.
________________________

SECOND ARTICLE [I-II, Q. 35, Art. 2]

Whether Sorrow Is the Same As Pain?

Objection 1: It would seem that sorrow is not pain. For Augustine says
(De Civ. Dei xiv, 7) that "pain is used to express bodily suffering."
But sorrow is used more in reference to the soul. Therefore sorrow is
not pain.

Obj. 2: Further, pain is only in respect of present evil. But sorrow
can refer to both past and future evil: thus repentance is sorrow for
the past, and anxiety for the future. Therefore sorrow is quite
different from pain.

Obj. 3: Further, pain seems not to follow save from the sense of
touch. But sorrow can arise from all the senses. Therefore sorrow is
not pain, and extends to more objects.

_On the contrary,_ The Apostle says (Rom. 9:2): "I have great sorrow
[Douay: 'sadness'] and continual pain [Douay: 'sorrow'] in my heart,"
thus denoting the same thing by sorrow and pain.

_I answer that,_ Pleasure and pain can arise from a twofold
apprehension, namely, from the apprehension of an exterior sense; and
from the interior apprehension of the intellect or of the
imagination. Now the interior apprehension extends to more objects
than the exterior apprehension: because whatever things come under
the exterior apprehension, come under the interior, but not
conversely. Consequently that pleasure alone which is caused by an
interior apprehension is called joy, as stated above (Q. 31, A. 3):
and in like manner that pain alone which is caused by an interior
apprehension, is called sorrow. And just as that pleasure which is
caused by an exterior apprehension, is called pleasure but not joy;
so too that pain which is caused by an exterior apprehension, is
called pain indeed but not sorrow. Accordingly sorrow is a species of
pain