Have you checked your RAM?
Long ago, I had on a previous machine one of two chips go bad. This meant frequent kernel panics particularly when using applications that can use suddenly lots of memory like browsers.
The bad news is, back then, TechTools Pro consistently claimed the RAM was fine. A few tech savy recommended I not trust that. I tried the now old but still good "memtest" and it showed immediate failure. TT may be better at detection now.
If that is the case, your RAM may be under warranty--mine was.
--J.D.