people cough, sneeze, itch around me

[amer6296]

im a 15 year old boy student and noticed that people have started coughing around my presence about 4 months ago where it all started when i was in my classroom and two girls were coughing in front of me and ever since then the coughing gets worse and worse week by week. i never stop thinking about it and i have tried talking to my father about this but he says "people are coughing because they are sick" and i know this is not why. when ever i walk past someone they cough or siff air through their nose and 3 days ago we came back from our trip in plane and it was hell, everyone was coughing ever 30 seconds 2 times in a row. i search all over the internet to see what other people have to say but everyone says its an odour issue and i know it's not true because i am clean. i am starting to go crazy and now i ask people why are they coughing. i keep asking my dad 3rd day why people cough near me like why, nope he says "they have a cold". how can everyone have a cold. guys it really would be nice if someone could discuss this hell with me, thanks