why does my macbook pro get so hot?

I bought my computer 8-25-15 ( August of last year) and it gets incredibly hot! I'm not sure why or what is wrong but this is insane! I love the computer but this is crazy! I can't even have it on my lap without it basically burning my leg.... It also seems to Lg quite considerably if I have more than 5 tabs open, any tips?

Thanks!