It is hard knowing what the problem could be without seeing the saw, but you might want to try running it at high speed without cutting anything to see if the chain gets anything more than just warm. If it does there is an oiling issue or the chain is too tight on the bar. If the chain only gets hot when trying to cut I would lean heavily towards an improperly sharpened chain, dull chain, (I don't know if it is possible to do) chain installed backwards, etc.
One thing to check as well would be to run the saw and chain for a few seconds in open air and then stop the chain and pull the chain by hand away from the bar along the bottom of the bar. All parts of the chain that run in the groove of the bar should be visibly wet with oil, if not there is an oiling problem. If the bar oil you are using is not thick and sticky enough for the outdoor temperature you are running the saw in (or if you are trying to just use motor oil), almost all the oil will just flip off the end of the bar instead of staying stuck to the chain as it ideally should. That will cause everything to run hotter. Remember to make sure the small oil passage holes at the end of the bar are kept clear of debris as well, and that the groove in the bar does not become packed full of sawdust. If it is packed full of sawdust in the groove of the bar you may have the wrong chain. The drive links (shark fin shaped protrusions that ride in the bar groove) are there to constantly clean the groove of sawdust and if that is not happening it indicates that they possibly do not extend deep enough into the bar groove to do their job.
On my Stihl chainsaws (MS260Pro and older 031AV) I go through a tank of bar oil about equal with a tank of gas, and if I point the tip of the bar at a light colored surface and spin the chain there is very little visible oil flipping off the end of the chain, it stays stuck to the chain very well.
If your chain chisels are dull, sharpened at the wrong angle, if the rakers are not set properly (even if the chisels are sharp), etc. it will often give the same symptoms as a faulty chain oiler, because the tremendous heat generated from the poor cutting will burn off the bar oil faster than it is replaced. Everything will discolor from the heat and you will lose the factory temper of the chain and bar which will then cause it to dull and wear very quickly from then on. It sounds as if that has already happened, so you are too late for that.
I would guess you are not getting any email replies from Stihl, because they probably get hundreds of emails a day wanting help with symptoms that sound like and are caused by user error 95% of the time and nothing to do with the chainsaw itself. Wrong or not, you have probably been lumped into that category by anyone reading your emails and as a result I can see both sides of that issue.
As a side note, look up some pics online of what chainsaw shavings should look like if the chain is good and sharp, and compare yours to the pics. If your shavings look more like fine circular saw sawdust, or if the shavings themselves are burned or darkened (from heat) your chain itself is not cutting correctly by a large margin. With a freshly sharpened chain, I can get shavings that are each long (1-4") and look just like miniature versions of chisel shavings from a hand chisel or hand plane for a good percentage of the sawdust bulk in wet or dry wood, so that is what you should be aiming for. Good luck, and keep us posted.
And last but not least, even if your chain is getting no oil at all, it will still cut fast if the chain is sharpened and adjusted properly, it will just wear much faster and you risk overheating it easily. If it is not cutting at all, proper chain sharpening is what you need to look into first and foremost.
