charging issue

when I charge my phone the iphone shows the battery percentage indicator but the battery is not increasing.

It will be stuck to whatever the no. is on the display of battery.- when I do a hard reset(home+power button) then the battery percentage comes really down like from 25% to only 8%.

-when I try to connect my phone with my pc the phone usb not recognized

- sometimes when I use my phone while charging the battery percentage will not increase.

-sometimes when i put my phone on charging when the battery is below 10% then, the phone gets restart again and again.

-when the battery is totally 0 and then i try to charge it up, the phone sometimes does not start and shows the red indicator on the screen but will not turn on.

- facing this issue from past . currently on ios 9.2.1

- when the phone gets to 100% charge somehow it does not show the full charge indicator on the battery.