If the purpose of pain and suffering was given by God for moral goals, than non-moral agents (i.e., other animals) would not need or have pain and suffering (or pleasure).

However, pleasure, pain and suffering were not given by god. They were evolved for biological reasons. It makes sense that pain and pleasure evolved: they help us achieve the biological goals of having children, eating, and avoid injury.

If our bodies were designed with a purpose, suffering would not be necessary, and would be unethical for a god to create. A god would need to only alert us to a problem, or a goal, without pain or suffering. Causing pain has moral implications, and God would be on the hook for all pain and all suffering by making that system in the first place.

Many religious people claim that pain and suffering serve some religious purpose. However the opposite is true. First, it clearly serves a biological purpose. Second, the goals it achieves are clearly not spiritual, and any spiritual goals that a god wanted could be achieved with an alert system that does not produce pain or suffering. Example: when a bully punches you, you feel pain. When a spouse embraces you, you feel pleasure. When a pen drops on your hand, you sense it, but it doesn’t set of your pain receptors, and is not interpreted as pleasure in your brain.

Pain and pleasure should be expected if we are simply biological organisms that evolved to meet biological goals. Pain and pleasure is not what you would expect from a loving, morally good God that had spiritual goals for us.