My mac is heating up so easily after internal HD replacement

I just replaced my original 256gb internal hard disk with a Samsung Evo 512gb. After having some troubles installing OS X El Capitan (took forever), I finally had access to my 'new' computer, and, as of now, I am definitely happy with the result. My only problem is that, even with only Safari or iTunes open, the computer starts heating up so much, and ventilation starts going (making a lot of noise), and never stops. Is there a solution to this problem, and is it in any way related to my new HD? Thank you so much in advance!

Giulio