My iphone 5s won't connect to a server

My phone wouldn't let me send pictures all day. Then it started to automatically restart itself. Now I have it turned on but it won't connect to any server or 3G, it just says "Searching...". I have tried restarting it and leaving it turned off and resetting the settings.. nothing is working. What do I do? (iphone 5s) By the way, there is a software update that is available but I haven't been able to update my phone because I can't connect to a network in order to do the update.