You need to check the logs, e.g. journalctl -b -p err|less More about journalctl here
Is there a way to figure out why my browser keeps on crashing?
[deleted]
do you experience crashing only on those two browsers? maybe try Tor or web or even brave?
- Edited
If the two browsers crash/freeze in both Ubuntu-based Pop_OS! and independent Solus OS, then the issue may be related to the way in which the browsers are set up.
In addition to checking the error logs as Pomon suggests, you might want to look at Firefox crash reports (type "about:crashes" in the address bar) and review "Troubleshoot Firefox crashes (closing or quitting unexpectedly)". The article links to numerous troubleshooting branches.
I can't speak to Vivaldi because I don't use it, but given that both Firefox and Vivaldi are crashing/freezing, I would look at non-default similarities (settings, themes, extensions and so on). Chances are that what is causing Firefox to crash/freeze is related to what is causing Vivaldi to crash. Get to the bottom of one and you will probably find the other.
Good luck.
Then there could be a fault with the graphics card, or a memory chip.
betsubetsubetsu But I am still experiencing some crashing particularly in Vivaldi and Firefox. I also have freezes sometimes which makes me have to reset the computer
I'm not reading this like everyone else. I'm reading sometimes OP has system freezes independent of the browser, and sometimes involving the browser.
I think the 2-browser thing is just a red herring (distracting coincidence).
It's DM and/or graphics-related, and/or hardware-related as suggested above this post.
Or both.
I was plagued by freezes for a year before figuring them out.
Either way, @pomon's journalctl command will be revealing.
betsubetsubetsu Maybe you have to try to disable hardware acceleration option for the browsers.
brent I'm not reading this like everyone else. I'm reading sometimes OP has system freezes independent of the browser, and sometimes involving the browser.
Reading more carefully ("But I am still experiencing some crashing particularly in Vivaldi and Firefox. I also have freezes sometimes which makes me have to reset the computer.") I can see why you think so. The error may be manifesting primarily in the browsers because the browsers are what are used the most. but the problem more general.
brent It's DM and/or graphics-related, and/or hardware-related as suggested above this post.
If the crashes/freezes manifest outside the browsers, hardware faults (e.g. RAM issues, graphics card issues) and/or interactions (e.g. hardware acceleration) are possible culprits. Full hardware diagnostics (preferably pre-boot) might be in order. I think Asus motherboards make provision for pre-boot diagnostics. The logs, both general and browser-specific, are going to give clues. It might also be helpful to keep notes of what was happening right before the crash/freeze occurred. Not high tech, but often a way to narrow the troubleshooting path if a pattern is identified.
pomon Will check the logs for this!! Thank you
[deleted] No not only, sometimes I even crash on Discord and RStudio
tomscharbach I'll be sure to try and do some full hardware diagnostics! Thanks so much for the advice!
UPDATE:
This seems to be happening to other apps as well. journal ctl doesn't really record anything about the crashes either so I don't understand where it's coming from.
I also tried installing steam (and also updated the drivers) and Steam won't open. I tried both Software Center versions and Flatpak versions. 
I believe this is a hardware problem but I don't know where to start with diagnostics.
betsubetsubetsu I believe this is a hardware problem but I don't know where to start with diagnostics.
Superb question. I'd also love to know if a linux tool exists that accurately measures health of chipset, memory, hdd, etc without the pre-fail, old age, or dying labels these s.m.a.r.t tools give everything including your brand new stuff..