Possible that laptop FAN is causing this problem, please follow the advice below:
1.Power off your laptop, now using your phone's flash light or other decent torch check the air vents of the laptop fan, we check for dust, thus may either easily noticeable or not, but if not does not necessarily mean its not a dust issue and vice versa. Therefore you may need to remove the back panel of the laptop.
2. Only attempt taking apart the laptop if you know what you are doing and completely free static, check youtube for help before attempting completely to get abreast of the situation.
3. Once your laptop panel is removed, check your fan, gently nudge with your finger and see if it spins freely, if it does not dont panic, now gently gain...