My iPhone 4S hangs (gets stuck or unresponsive) when deleting photos from the camera roll or use Messages app

I am now on my third replacement phone from Apple because of this issue. My iPhone 4S frequently hangs (gets stuck), without response, when I click on the trash icon to delete a photo, for about 20-30 seconds before becoming responsive again. I notice that this problem of freezing happens also when I use my Messages app for texts. There is no crash that occurs because the app responds after hanging for some time, therefore does not create a crash report to be sent to Apple. I never had this problem on my iPhone 4, and truly regret upgrading to the new device. I bought this phone for the faster processor, however I ended up with a device that is much slower and unresponsive. At the instruction of the multiple geniuses at the Apple store, I've restored the phone numerous times and set it up as a new device to no avail, and have lost app data every time. I've had three different phones now, and the genius cannot resolve my issue. they've even done what's called a DFU mode restore to restore the device firmware, yet no fix. Is anyone having similar issues? I'm starting to think its a software issue, although the apple store kept replacing my phone with a "remanufactured phone" even though I was within the 30 day return period. When I asked to get a new phone from the box, they told me it couldn't be done since I had my device replaced with a repair model already.