The heatsink is probably blocked with dust and other assorted crud.
The problem with laptops (and a reason I never buy a high-powered one) is that the cooling fins for the heatsink can not be accessed without performing the equivalent of open heart surgery on the computer.
If your laptop is still under warranty, you can go and argue your case at the service centre; if it’s not, I would suggest finding someone competent to open it up and clean out the crap. I would only recommend cracking it open and cleaning it out yourself if you are either brave or really enjoy trying to put Humpty together again.