" Quite Simply, I might say: "I would like to get rid of that tick that's been biting me all day." I wouldn't say: "I have to be free from that tick." And that is why I might use "rid of" with a cold, instead of "free" (it doesn't matter https://www.diigo.com/item/note/aw0y1/682s?k=0731bbd4e9173fec6c77898099cb27f1