there are a couple of things you need to check,
#1 as mentioned above hingepins check both inner and outer for bends.
#2 shock seals - as these get old they tend to become hard and restrict the movent of the shock shaft, especially with ultimate shock seals.
#3 the shock shafts may also be bent
in the past if I've found my shocks not returning properly these are usually the reasons
Adrian
