iphone 5s charge problem

Dear All,

This is Irfan Turhan from Turkey. I bought my iphone 5s from NYC in 2013 around October. So, i have a charge problem. My cable is New and i checked it with another iphone and it is working. For mine, i am suppose to force it, then it works. My question is; i Will be in NYC on 11-12 July 2015. Your Store on 5 th street can fix it? I am not sure if my iphone has a guarentee still? Moreover, if i want to replace with iphone6 my 5s, is it possible by paying gap?