iPhone SE - force rebooting gets into a loop My situation is a bit complicated.
I have an iPhone SE with iOS 9.3.5.
I connected my iPhone to a rental car's audio system and something bad happened. The lock button stopped working and it is spontaneously "clicked" (software-wise) randomly. Sometimes I even get the turn-off screen that is usually displayed after a long lock-click, expect I don't press anything.
I've tried to do a force-reboot (holding the lock and home buttons for a few seconds), the iPhone get turned off, but then immediately it gets into a loop, and the only way to get it to load is to connect it to a power source. This happens also after I simply turn it off (using the accessibility software solution).
I now back-upped the phone to my iTunes, and deleted all of the data so it'll be new-like but this did not help the problem. All of the above symptoms are still happening.
Any ideas on what else I could do?
I don't think this is related to plugging into the rental car.  

I also have (had) an iPhone SE and it experienced the exact same problems.  I took it in and was told the sleep/wake button on top was bad.  The repair place told me they don't bother repairing these models anymore because the parts are very hard to find; this model has a bad problem with this type of button failure.  If you google it you'll see. 

I ended-up going to Best Buy and they recycled it for free.  I think you're out of luck unless you can find a place to repair it.