What do you understand by disease?
Let us take the example of a terrorist attack on our country like 26/11. It was one event which caused lot of damage, destruction and pain to people of the country. Now, before 26/11 also terrorist were making attempts to cause destruction, but they were not successful in many instances. They failed because our defenses and intelligence worked to their full potential and prevented the actual occurrence of such damages.
This situation of defenses working to their full potential can be compared to a state of health.
Now, when the terrorist got successful in creating damage, the whole country realized that there were lapses in our defenses. They did not function to their fullest potential, thus giving the terrorist an upper hand to create destruction.
This situation when the defenses are not working to their fullest potential is comparable to a diseased state in our life. When one falls ill, there are lapses in our internal defenses and we see this in the form of tissue destruction, suffering, pain, and altered blood biochemistry-i.e. sickness.
During the 26/11 attacks, though there were lapses in our defenses, we nevertheless could limit the chaos and destruction to the two hotels only. It did not spread through out the whole city like it happened say for e.g. in Iraq. This is because the defenses forces still gave a fight, though with some effort it was able to finish the terrorist.
Similarly, in a disease state though there are lapses in our defenses, the body still is attempting to fight the stressor. It is due to this fight that we experience pain, suffering. Disease therefore represents the fight between the person’s defenses and stressors.
To sum up, disease is a war between the internal defenses and the stressor. During this time, the defenses are functioning at a lower than normal level, hence the pain and suffering.