Sounds as if the chain rolls direct over your swingarm. metal on metal
i cant even see the black chain guard (right term???) on your swingarm.
Did you swap to a 16 sprocket ?
If you stretch and change front sprocket you must use lowering links to avoid just what you have now.
If you dont change links, a longer swingarm will have the same effect as risinglink (my terms)
redoo work and mount the black plastic guide.
YES, you need the black piece that the chain rubs on. It acts as a spacer, IIRC
And it is hard to tell, but it looks like some of the links are bound up and do not want to move??
I had an issue similar to this...when i put it on the stand and spun the wheel slowly by hand I could see the chain make a slight shift in it's position as if the links were getting jammed up together and not wanting to turn. used some liquid wrench after taking the tire mounts off (not the axel obviously, but gave it some room to move freely) and it got a lot better. I'm pretty sure it started due to the front sprocket wear and misshifts when riding it hard. Replaced the sprockets and it worked fine but I'd also check for wear on your chain slider (whatever the piece of steel is called that your links slide across when coming over the top of your bike) to make sure that it's straight and not jammed up with too much lube putting a sideways tension on your chain.
-easy way to test that one is put it on a stand and let it idle in neutral while standing behind the wheel looking town the chain; a little movement is easy this way.
Edit, after watching....where the hell is your chain rail guide in the first place? don't you have to have that to keep the chain from sagging into the swingarm where it meets the top of the front sprocket???
YES, you need the black piece that the chain rubs on. It acts as a spacer, IIRC