Do cold blooded animals feel pain?

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).