"a severe pain" is correct and usable in written English.
You can use it when describing a feeling of intense physical discomfort. For example: "He was suffering from a severe pain in his back."
He was trying to keep himself through a severe pain if that's the way.
And as he did so, he felt a severe pain in his chest.
But soon she began to feel a severe pain in her back and learned that she had three herniated vertebrae, she said.
Nadal, a four-time French Open winner, complained of a severe pain in his right knee, in April at a tournament in Miami.
About two o'clock in the morning he is awakened by a severe pain in the great toe; more rarely in the heel, ankle or instep...
Lord Graham of Edmonton who, flying Club Class from Australia, developed a severe pain in his right leg. Dentist Ann Egerton whose life was saved by her GP husband on a BA flight back from South Africa.
Breakthrough pain is best described in patients with malignant pain, leading to a number of adverse effects including a more severe pain syndrome.
A sudden, severe pain in the ear without a cold or sore throat is unusual, and may herald an infection and should be referred to a doctor.
Recent studies conducted by physicians from the University of Oslo and Weil Cornell Medical College confirm the lesions and tenderness caused by FGS lead to bleeding on contact -- causing a constant, severe pain that can be exacerbated during work, chores or intercourse.
A more severe pain on kneeling for subjects with knee OA compared with those with hip OA would be an example of DIF.
