Galaxy S4 email and contact issue

[Spiceyadswan]

I purchased my S4 in July and it worked great until about two weeks ago. I decided to restrict background data on a couple applications and it then went in to a continuous reboot cycle where the phone would stay on for less than five seconds, freeze then reboot. Eventually a hard reset was performed and that seemed to solve the problem. I then decided to play with restricting the background data again just to see if I could recreate the problem and I could get it to do it if I restricted Facebook background data. As soon as I would leave wifi it would start rebooting my phone. I had to put it in airplane mode at start-up to get it to stop and change the setting back. That seemed to solve the problem. So my new problem is this. Ever since that hard reset and issues with the reboot cycling, my contacts and emails have been sluggish and sometimes completely unresponsive. I will admit that I have over 8k contacts on my phone and they are "joined" via linkedIN, FB, Google+ and my exchange account. Obviously, I use this for work and the number that are actually joined is just a small fraction of the overall 8k. What is happening is I bring up my contacts and it remains blank. I also try to open email and it usually has no problem showing me emails but if I go to reply or start a new email it goes black. Eventually it will say that "Email is not responding, do you want to close it" Wait and stop are the options. I can hit "wait" a few times and eventually it will show up, I am talking about minutes here not seconds, but that is just unacceptable. It seems as if it is trying to do something in the background or is just having issues with searching contacts. I am not sure. I can't search contacts, I can't send emails, so unless I know a number I can't use my phone like a phone.
It had no issues like this prior to the continuous reboot. I guess this is what I get for trying to play with my phones settings.

Any help would be appreciated.