Q: iPhone 6 Plus screen freezes after iOS 9.3.1 update

In my opinion I would Press my home button and wait for the slide to power off option to show, then hold your hold button until the  slide to power off option goes away.(This clears your cache).

I'm having exactly the same problem. It started with 9.3 and so I downloaded 9.3.1 but no improvement. I use my phone a lot and it has frozen about 20 times today. I have tried a system restore and all was ok for about 20 minutes after which, back to intermittent screen freeze. Apple - please fix!

Steve, it is not happening on my end nor reported as common here.

You posted that you tried a forced restart but try it again please. Hold down the Home and Wake/Sleep buttons at the same time for about 15-20 seconds until the Apple logo appears. You will not lose anything.

If that does not help then try a system restore.

First backup your device using iTunes. Then import your photos to your computer and copy all important data. Try restoring from backup first and testing it. If it does not help, you may have to restore as New and reconfigure from scratch as the backup could be corrupted. For this reason it is important to have your photos and data saved separately from the backup.

https://support.apple.com/en-us/HT201252

I got my 6s+ three weeks ago after using Android for the past 8 years.  When I powered it on for the first time, I signed in and set everything up.  A couple of days later I got the update notification, so I updated.  I got the same screen freezing issues a day later, but my wife's 6s was fine.  I did a factory reset and it's been running fine since.

MY phone freezes CONSTANTLY also!!! The most annoying thing ever!!! And the hard reset does not improve it! I am tired of being the test dummy for Apple products! This is ridiculous!! Who has time to constantly reset their phone? how am I supposed to save my data separately?

I'm having the exact same problem... I'm going to go to an Apple store today to see what they say. I'll let everyone know.

Exact same problem.  My battery was getting long in the tooth on my iPhone 6, so I had it replaced at Apple, only they said we can't replace it, here's a new phone.

Now it freezes every hour.

I had this same problem about two months ago. I went to Apple. One tech told me that my phone was bent (it wasn't). We ended up speaking to another tech who said that the best he could do for me was a discount on a new phone. So, for over $300 we replaced my 6 plus. Two-ish weeks ago I started having it freeze up on me again. For those of you who have not had this problem, I can assure you I have done ALL of the recommended hard resets and restores I could do, and none of them have fixed the problem. All diagnostics done at the apple store came back that my screen worked fine. I had two apps that were glitchy, so I have deleted them. Doesn't fix the problem.

My husband and I are going to do a restore and switch phones to see if it's a hardware or software problem. I will update here after we give it a few days to see what happens.

I hope the restore works for you.  My phone was a fresh restore.  It's not hardware , it is IOS.  If I tap on an icon and it freezes, then I wait 45 seconds to a minute the icon eventually flashes and takes affect like it is queued.  IOS is busy doing something it shouldn't be.  It is in a loop or something. I'd be willing to bet it is IOS.

Update: I never got around to switching phones with my husband. During my shift last night my phone lost it's mind. It wouldn't hardly work at all. I was doing hard reset after hard reset. At least 10 times in less than an hour, just to try to delete apps and change settings. The key was turning off the fingerprint scanner! Not only is my phone no longer freezing up, but it's running faster and a few errors that I seemed to have occurring on a regular basis are now gone. I never really noticed I was having such a buggy phone.

Now I'm mad that I had to buy a new phone a few months ago, because of the fingerprint scanner. GAH!

I think I have my freezing problem resolved.  After working with Apple phone support and restoring the phone to factory a couple of times, we agreed that we had exhausted all the software possibilities.  So they told me to return to the genius bar and they felt my problems were hardware related.  Once there, Apple replaced the second phone with new one. And we restored my iCloud back up.  This time, with the new replacement phone, I was successful and it appress to no longer be freezing.

I have the same annoying problem. I notice my iphone 6+ is starting to freeze up or lag after i updated my iOS to 9.3.1, the problem is intermittent ...I tried the soft reset (hold home+power button) and also tried back up + restore factory setting + restore back up, but the problem is still there. What i haven't done yet is restore factory settings and then download the apps one by one.  I hope Apple could give an update and fix about this issue we're addressing.