MJ Andrew, Access to Adequate Medical Care is a Right (along with Darwin Catholic's Thoughts on Health Care as a Right.)
I would argue that a right pertains to the virtue of justice, and not to charity. Is a physician bound to treat another due to charity or to justice? Is health care a common good that is distributed? Health is a good that is common by predication, not by cause. How can it be argued then that it is common because there is common ownership? Do we have common ownership (or a claim) over the services of a physician?
(See also Mr. Andrew's Locke on the Law of Nature: Breaking with Tradition.)