You need a bit of time to see the difference upping your cadence can make.
As a former masher (low cadence, high effort, high speed), my knees hurt occasionally, occasionally quite badly. I was fit, I could hammer myself, but it did hammer the knees .
Decided to spin more, at first it seemed counter productive, felt horrible, too slow, but within a month I guess, I found I could almost maintain the speeds I used to do...with a lower, more forgiving gear ratio.
On a 50/40 chain set, I could fairly motor along on the 40 and rarely felt the need to get onto the 50t ring
What gears does OP have one his bike I wonder ?