My iPhone 5 has not been working properly please help!!

I have a 16GB iPhone 5 with the latest update (iOS 7.1.2) and lately (about a week or so) it's not been working right. It first started where the screen would freeze and then I'd have to click the power button and return to lock screen I get it to work again, or sometimes even turn off my phone. Then one day I tried to take a picture and it wouldn't let me?? So I turned off my phone and when I turned it back on it worked again. Then the other day I went to play music and it wouldn't let me. First I tried from the itube app then thought maybe the app wasnt working, so I went to my iTunes music on my phone and that wasn't working. It wouldn't let me press play/pause/next. basically it wouldn't let me do anything and then it just froze. I put it to sleep and went back to my music about 30min later and it was fine. Then today my screen froze so I held down the power button to turn it off. Nothing happened for 10 seconds then the screen just went black, no little spinny thing like what normally comes up when it powers off. Then no matter what I did it wouldn't turn on. I looked up on here how to fix this and found a solution (plugging it into my computer and holding the power and home button for 20 seconds). Anyway, basically what my problem is is that I dont want my phone to be like this? Should I take it in to be looked at or is there maybe an app causing this ?? I honestly have no idea and it just recently started being like this (I've had this phone for 3 months and it's new. It still has about 5GB of space left). Please let me know if you have a solution or if this phone just is like this. Sorry if this isn't very descriptive :/ Ive been able to get my phone working again every time so far, but next time I might not and I really want to fix it. Thank you!!