iPhone 4 dosent have a Lightning Port (remember?)
@ isfiisfar: How are you brother??? 
1) Did you try or have you jailbroken it?
2) Does it turn on when you plug it into a wall charger? if it does how long does it charge?
3) Ya and check the battery
4) From your 1st post : 1: when i capture a pic.. the phone immediately reboots...
I smell software there
i have observed when i was on iOS 8 (really buggy!!!!!) some times thou (while unlocking)
Have you used iTools or iFunbox to put your songs? Have you put some photos too? and again this had happned on WD7 when i restored backup using iTools... 
hey br0... m good, hw r u,,,,
my iphone not activated.. so cant jailbreak...
the charging issue fixed by changing the usb port...
but the problem m still facing is the phone shutdown issue,,,,
i think its battery cauz when capture a pic... it turn off immediately not shutdown...
BTW M on os 7.1.2