Nope. Multiple instances of "
lifelink" on a creature are redundant (they don't stack).
However, if you have a trigger that says "when <x happens>, you gain life", then that's a different story. For example,
Soul Link, though it does the same thing as
lifelink, is not "
lifelink." Therefore, it stacks with itself or
lifelink. However, no. Multiple
lifelink instances are redundant.
702.15.
Lifelink702.15a
Lifelink is a static ability.
702.15b Damage dealt by a source with
lifelink causes that source’s controller, or its owner if it has no controller, to gain that much life (in addition to any other results that damage causes). See rule 119.3.
702.15c If a permanent leaves the battlefield before an effect causes it to
deal damage, its last known information is used to determine whether it had
lifelink.
702.15d The
lifelink rules function no matter what zone an object with
lifelink deals damage from.
702.15e Multiple instances of
lifelink on the same object are redundant.