ride height

I notice that one side of my dino is 2.5 cm higher on one side (Front) ...somebody told me 'Oh this is normal' .... really ? ...the shockers were replaced recently...could it be that the shockers were not adjusted correctly or more likeley the spring wasnt changed at the same time and if the problem is the latter...how difficult is it to change the spring.....do I need a special tool to compress it ....?