Why would you run a norton scan at the same time as playing Overwatch? To stress the CPU purposely?
There may be a cooler that will perform better for you now, but if you upgrade the case later there are better options again, so you might want/have to upgrade the cooler again. It depends what cooler you were considering putting in the case right now.
The room temp is fairly warm and surely affecting your case and CPU temps but I think we need to get a better look at how your system is set up and running. Prolonged temperatures that high will slowly degrade the CPU more quickly than if the temps were kept lower. So yes, those temps aren't ideal.
Do you have the program HWiNFO? If not can you install it and then post some screenshots of all of the values. You'll have to scroll the bar down to take multiple screenshots. Try to get a screen shot when the system is at idle, no other programs running using the CPU, like a norton scan. Then reset the values (clock looking icon) and play Overwatch for a while, leaving HWiNFO running in the background. As soon as you exit Overwatch take screenshots of HWiNFO straight away so we can get a look at the max and average CPU temps. Don't run a Norton scan at the same time, only run Overwatch.
There may be something else going on with your system or it could be that the room is really warm and the cooler you have is too weak. Where is the fan configuration currently at? Do you put the ML140's in? Have you tried getting any fans up top?