It would depend on the cold blooded animal you are talking
about.
If you are talking about reptiles and amphibians, it is likely
that they feel pain to some degree.
If you are talking about fish, it is very debatable. Some
studies state that they do feel pain, but some say they do not.
This is because the brain of a fish is very different from that of
a mammal, being brainstem dominated. Many behavioural studies have
provided some evidence that they do indeed feel pain, though those
studies have been debatable.
If you are talking about invertebrates (which are all cold
blooded), the current evidence seems to favour that the majority do
not feel pain, as they lack a spinal cord and cortex. However,
there is behavioural evidence of pain in several invertebrate
species. Examples include Gastropods (i.e. snails and slugs) that
belong to clade Heterobranchia (such as the garden snail and slug),
decapod crustaceans (ex. crabs, lobsters, shrimp) and flies
belonging to the family Drosophila. All three of these examples
have had at least one species demonstrate operant conditioning to
negative stimuli. Octopuses have fairly large brains and appear to
have nociceptors, and there is some evidence that they feel pain.
However, evidence is scant for other invertabrates. Additionally,
not only is there absence of evidence of pain in the majority of
insects, but there is also evidence of absence of pain in them (ex.
injured insects don't limp, locusts continue normal activity while
being eaten).
