Here are sentences where you can use painful:
When John was on the battlefield fighting to save his country and his men, watching people die before his eyes was painful to witness.
When he had to have the splinter removed, it was painful to bear.
The immunization was long and painful.
Her loneliness was painful to watch
When Julie was in the throes of childbirth it was very painful.
Snapping your banjo string can be quite painful
A dislocated shoulder or knee can be quite painful.
Example sentence - The dentist said the procedure would be painless but it felt painful to me.
His painful injury was lamentable; everyone was sorry for him.
Bunions on the feet can be very painful, and frequently are treated with surgery.
Chilblain refers to Chilblains, which are a painful inflammation of blood vessels.
When I broke my ankle, it was very painful.
Upon sagacious reflection, Simon realized that his parents' rebuke though painful, was salutary.
It was painful to try to do the splits in gymastics at first, but I finallly got it!