Chain or sprocket problem ?

[Gone in 60]

I've had a similar situation with my Bonneville. Checking the chain slack with the bike on the sidestand, as it's supposed to be checked, I found it consistently loose except for one area, where it was much tighter. But on the center stand, it was consistant throughout its length. I didn't worry about it too much, knowing that the chain was nearing the end of its lifespan anyway.