For starters, if you yourself are saying your chain is too tight.....then it's too tight.
So you can begin somewhere by sorting that out so that it's correct. It's generally around 35mm of play on the lower middle part of the chain, but another way is with your finger push the chain up near the front end so that it just comfortably touches the bottom part of the plastic chain guide.
Make sure you slacken the rear brake caliper bar when using the rear wheel adjusters too otherwise there will not really be much to adjust on the right side.
What i normally do is slacken the adjusters, then push the wheel forward so i can nip each side up a bit at a time from scratch, until i think it's about right. The markers on the swing arm are a good guide, but not necessarily 100% accurate, so when you think the wheel is straight spin it backwards and all you should hear is a gentle purring sound of the chain.
Any other noises, like grinding, clunking, etc, means the wheel is still not straight or the chain is still too tight.
Once you're happy with the chain slack and the sound of the wheel spinning then torque it up to the correct spec.
When was the last time your oil was changed, and have you got the right amount in the sump?
It's possible older oil at high speeds could cause unwanted noises, even more so if there's not enough of it.
If you don't know when it was last changed, or it is old, then i would change it.
To correctly check the level, as per manual, put the bike on level ground on the centre stand then "start the engine" and let it run to circulate the oil for a minute.
Switch the engine off then looking at the sump window let the oil settle, it will only take about another minute to do so, but when it does this will be the correct level.
We've kind of agreed over time that the oil level should be towards the upper level marker rather than around the middle of the two markers, to prevent the oil level light flickering on hills or acceleration.
These are two areas where i would begin, to see if that helps at all.
This is now at least the third recent post where a noise has tried to be described but everyone has their own way of saying things so it can be difficult to assess without riding the bike ourselves.
Worse still, like your problem for example, it's a noise that happens when moving or at higher speeds, so you can't even record the noise either which is even more annoying.
I would start with the two simple things i've mentioned but if it's still bothering you or happening afterwards then you might wanna get a second opinion from a mechanic who'll need to give it a spin to try and replicate the noise.
I understand what it's like though, i completely know my bike by the noises it makes and whether they are right or wrong, so a new person riding it may not hear anything untoward at all, just general bike noises.
