Do I need a balance charger if i use a Protection Circuit Module for Li-ion batteries?
Those modules protect against over-charge, over-discharge and over-current, but they do not have a balancing function. Cells that are matched and charged to the same voltage initially should not need balancing. However if you are worried that your cells that might go out of balance then you can use a PCM with balancing such as this:-

4 cells 8A w/balancing Li-ion Lithium 18650 14450 Battery Input Output Protection

The balancers in this PCM bypass up to 42mA from each cell as it becomes fully charged. To properly charge the battery you still need a Li-ion charger or power supply which provides constant charging current and limits the peak battery voltage to precisely 16.8V.