Fan? maybey

Hey my laptop has been getting worse and worse every time i turn it on (mostly only when i have transported it like going to and from my mom's and dad's). It makes a sound every time something starts up I think it is my fan or whatever it's called that cools my laptop because it sounds like a fan scrapping on plastic or something. After about 15 minutes i think it must adjust because it starts up but doesn't scrape anything. I was wondering what it is, if it is a big deal, and how to fix it(or if i should have someone else fix it). sorry my computer vocab is a little limited. Thank you!!