What can be done about my husband's ongoing stroke pain, and does it mean there's another one coming?

Head pain is not common during, or after, a stroke. When it occurs, it may be a sign of 1) bleeding, 2) a tear in one of the arteries, 3) See also:
Is there anything that will help relieve my dad's pain after his stroke?

See all 502 questions about Stroke a clot in one of the veins, 4) opening up of smaller arteries when one of the larger ones is occluded, or 4) a side effect of his medicine. I typically evaluate this by obtaining an image of the brain and its vessels, and checking the medication list. One medicine that is not infrequently associated with headaches is Aggrenox. If he is taking that, it may be worth trying a different medicine.

If imaging is negative, and it does not appear to be one of his medicines, than the headache sounds more benign, and can be treated conservatively with headache medicines. There are several medicines that help prevent nerve pain after stroke, and you should inquire with your Neurologist about an appropriate choice of medicine.

I hope that helps.