I'm having various charging problems?

My phone will only charge if switched on first and then plugged in for charging. It switches itself on if plugged in first and won't charge, then if you remove the charger it switches itself off.

My phone is stuck at between 1-5% charge (it seems to go up and down randomly each time it's on?) and won't turn on, it flashes the light like it does when the battery is dead. However, it will switch on if I plug the charger in but will not charge (however the battery seems to not go down either). This basically means I can't use my phone unless it's plugged in. I have the same problem with every charger I use and it doesn't matter whether it's plugged into a USB or the mains.

Help?