It depends on what to hurt. In most cases, I never noticed this, on the contrary, when you are sick and sit at home on sick leave, there is more free time and there is nothing to occupy yourself with. Moreover, I noticed that with coughs and colds, smoking even helps to relieve symptoms: relieves coughing attacks, returns the voice, breaks through the sense of smell, in most cases, smoking helps to remove sputum, since sputum itself comes out together with the tar when coughing. I call it tobacco inhalations and use them in complex therapy
Because smoking is, in principle, an unnatural habit for our body. During an illness, the sensation is exacerbated and the body still manages to get through to the limbic system that it is better not to smoke. That's why I don't want to smoke. It’s just easier to recover.
In the same way, the appetite of people with high fever disappears for a while, so that growth hormone increases -> immunity increases -> the disease is gone.