Sir,when we change place or go to some other places or weather changes, we r most likely to get cold,fever or fall ill. why??

Good question: This is a very interesting observation and I think we need specific studies to understand this. Here is what I think happens. Travel will stress our bodies and then, we hit a different temperature and general microorganism content in the air, that our immunity being in a low state has to deal with. The result is a higher chance of getting an infection.