iPhone SE Won't Stop Buzzing

So I have an iPhone SE that I've had for a little over two years, and it won't stop buzzing. I say *buzzing* because we passed vibrating a long time ago.

SYMPTOMS

The iPhone, as I said, won't stop vibrating. It seems to vibrate whenever the screen is powered on, although it does vibrate intermittently while it is off as well. The only time it does not vibrate is when the phone is completely powered off. But the moment the screen comes on, be it from pressing the Power button, the Home button, or plugging the phone up, it immediately starts vibrating. The vibrating varies from a *low rumble*, you might say, to vibrating so forcefully and at such a high pitch that I actually worried that it might burst into flames in my pocket. Maybe that's a little extreme, but I'd never heard such a high-pitche whine come from a phone in my life, like my phone was screaming in pain. The pitch and strength increases and decreases, seemingly at random, and as it currently stands, it's rather consistent with how a phone's vibrate should sound, although it has vibrated, shall we seay, 23 out of the last 24 hours. All other functions of the phone work just fine, it's just the phone sounds and feels like hair clippers. Lastly, it has been doing this for several days, though I had about 3-4 days when the phone acted perfectly fine (except then it wouldn't vibrate at all, but honestly that was an upgrade), only to randomly have this problem come back with a vengeance; this is when the phone began vibrating like it was having its circuits plucked out one by one.

WHAT I'VE TRIED

- Submerging the phone in rice. Maybe some splash of water happened to land just right on the phone (maybe into the speaker?) to cause something to short out and malfunction.

- Hard resetting the phone with the Home and Power buttons, held from 7 to 30 seconds. There was a brief stint when the problem first started happening when I hard reset it, and the screen never got past the Apple logo (with the phone vibrating away the whole time), but that was resolved when I actually plugged it up to charge. This is also the start of the ceasefire when I thought this problem had gone away, but it came back a few days later.

- Letting the phone battery drain until not even the *Battery Is Dead,Connect to Power* graphic showed up on the screen. Interesting point, the phone vibrated even for those few seconds that that graphic is displayed. Phone resumed vibrating the moment I plugged it in to charge.

- Updating the software, as I had one of those that I had been putting off.

- Restoring the phone software completely.

- Waiting for whatever mechanism in the phone that actually causes said vibrations to finally burn out, something that, to me, at least, doesn't sound that unlikely, given I've already had the phone a couple years, and I'm fairly certain whatever it's doing is well outside it's designed performance parameters, especially when it tried to vibrate itself to death. I could always be wrong, of course, but something has to give sometime...

As it currently stands, the phone is sitting next to me, buzzing away, while I wait for the backup to be restored. So give it to me straight, docs, is this the end? I know this phone isn't under warranty, and I'm located in Germany, currently, where I don't even know where I could take or send it for repairs. So, if the answer is simply *send it in for repairs or buy a new phone*, that's understandable and accepted. But before I write it off as a loss and retire it, is there anything whatsoever I missed, or anything whatsoever else I could attempt to fix it once the backup finishes and I can use the phone again?

You guys are the best, thanks in advance.

(Also...someone please just clear up my paranoia, all this vibrating isn't going to make the phone catch fire or anything, is it? Stupid question, I know, but it's doing something it shouldn't be, and I put it under my pillow to muffle the noise so I can sleep tonight, but I'd hate to find out that you're actually not supposed to keep it powered on while you do this, or the phone will overheat or something and next thing you know my living room is on fire...)